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Huang Z, Bai Y, Zhao Y, Liu L, Zhao X, Wu J, Watanabe K, Taniguchi T, Yang W, Shi D, Xu Y, Zhang T, Zhang Q, Tan PH, Sun Z, Meng S, Wang Y, Du L, Zhang G. Observation of phonon Stark effect. Nat Commun 2024; 15:4586. [PMID: 38811589 DOI: 10.1038/s41467-024-48992-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Accepted: 05/15/2024] [Indexed: 05/31/2024] Open
Abstract
Stark effect, the electric-field analogue of magnetic Zeeman effect, is one of the celebrated phenomena in modern physics and appealing for emergent applications in electronics, optoelectronics, as well as quantum technologies. While in condensed matter it has prospered only for excitons, whether other collective excitations can display Stark effect remains elusive. Here, we report the observation of phonon Stark effect in a two-dimensional quantum system of bilayer 2H-MoS2. The longitudinal acoustic phonon red-shifts linearly with applied electric fields and can be tuned over ~1 THz, evidencing giant Stark effect of phonons. Together with many-body ab initio calculations, we uncover that the observed phonon Stark effect originates fundamentally from the strong coupling between phonons and interlayer excitons (IXs). In addition, IX-mediated electro-phonon intensity modulation up to ~1200% is discovered for infrared-active phonon A2u. Our results unveil the exotic phonon Stark effect and effective phonon engineering by IX-mediated mechanism, promising for a plethora of exciting many-body physics and potential technological innovations.
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Affiliation(s)
- Zhiheng Huang
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yunfei Bai
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yanchong Zhao
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Le Liu
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Xuan Zhao
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Jiangbin Wu
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Wei Yang
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Dongxia Shi
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Yang Xu
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
| | - Tiantian Zhang
- CAS Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing, 100190, China
| | - Qingming Zhang
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Science and Technology, Lanzhou University, Lanzhou, 730000, China
| | - Ping-Heng Tan
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
| | - Zhipei Sun
- QTF Centre of Excellence, Department of Electronics and Nanoengineering, Aalto University, Tietotie 3, FI-02150, Espoo, Finland
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong Province, 523808, China
| | - Yaxian Wang
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
| | - Luojun Du
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
| | - Guangyu Zhang
- Beijing National Laboratory for Condensed Matter Physics; Key Laboratory for Nanoscale Physics and Devices, Institute of Physics, Chinese Academy of Sciences, Beijing, 100190, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong Province, 523808, China.
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2
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Kerwin B, Liu SE, Sadhukhan T, Dasgupta A, Jones LO, López-Arteaga R, Zeng TT, Facchetti A, Schatz GC, Hersam MC, Marks TJ. Trifluoromethylation of 2D Transition Metal Dichalcogenides: A Mild Functionalization and Tunable p-Type Doping Method. Angew Chem Int Ed Engl 2024; 63:e202403494. [PMID: 38551580 DOI: 10.1002/anie.202403494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Indexed: 04/24/2024]
Abstract
Chemical modification is a powerful strategy for tuning the electronic properties of 2D semiconductors. Here we report the electrophilic trifluoromethylation of 2D WSe2 and MoS2 under mild conditions using the reagent trifluoromethyl thianthrenium triflate (TTT). Chemical characterization and density functional theory calculations reveal that the trifluoromethyl groups bind covalently to surface chalcogen atoms as well as oxygen substitution sites. Trifluoromethylation induces p-type doping in the underlying 2D material, enabling the modulation of charge transport and optical emission properties in WSe2. This work introduces a versatile and efficient method for tailoring the optical and electronic properties of 2D transition metal dichalcogenides.
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Affiliation(s)
- Brendan Kerwin
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
| | - Stephanie E Liu
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University 2220, Campus Drive, Evanston, IL-60208-3108, USA
| | - Tumpa Sadhukhan
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
- Department of Chemistry, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, 603203, India
| | - Anushka Dasgupta
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University 2220, Campus Drive, Evanston, IL-60208-3108, USA
| | - Leighton O Jones
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
| | - Rafael López-Arteaga
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University 2220, Campus Drive, Evanston, IL-60208-3108, USA
| | - Thomas T Zeng
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University 2220, Campus Drive, Evanston, IL-60208-3108, USA
| | - Antonio Facchetti
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332, United States
| | - George C Schatz
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
| | - Mark C Hersam
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University 2220, Campus Drive, Evanston, IL-60208-3108, USA
- Department of Electrical and Computer Engineering, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
| | - Tobin J Marks
- Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, IL-60208-3113, USA
- Department of Materials Science and Engineering and the Materials Research Center, Northwestern University 2220, Campus Drive, Evanston, IL-60208-3108, USA
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3
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Cai CS, Lai WY, Liu PH, Chou TC, Liu RY, Lin CM, Gwo S, Hsu WT. Ultralow Auger-Assisted Interlayer Exciton Annihilation in WS 2/WSe 2 Moiré Heterobilayers. NANO LETTERS 2024; 24:2773-2781. [PMID: 38285707 PMCID: PMC10921466 DOI: 10.1021/acs.nanolett.3c04688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 01/22/2024] [Accepted: 01/23/2024] [Indexed: 01/31/2024]
Abstract
Transition metal dichalcogenide (TMD) heterobilayers have emerged as a promising platform for exploring solid-state quantum simulators and many-body quantum phenomena. Their type II band alignment, combined with the moiré superlattice, inevitably leads to nontrivial exciton interactions and dynamics. Here, we unveil the distinct Auger annihilation processes for delocalized interlayer excitons in WS2/WSe2 moiré heterobilayers. By fitting the characteristic efficiency droop and bimolecular recombination rate, we quantitatively determine an ultralow Auger coefficient of 1.3 × 10-5 cm2 s-1, which is >100-fold smaller than that of excitons in TMD monolayers. In addition, we reveal selective exciton upconversion into the WSe2 layer, which highlights the significance of intralayer electron Coulomb interactions in dictating the microscopic scattering pathways. The distinct Auger processes arising from spatial electron-hole separation have important implications for TMD heterobilayers while endowing interlayer excitons and their strongly correlated states with unique layer degrees of freedom.
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Affiliation(s)
- Cheng-Syuan Cai
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Wei-Yan Lai
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Po-Hsuan Liu
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Tzu-Chieh Chou
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Ro-Ya Liu
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
| | - Chih-Ming Lin
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Shangjr Gwo
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
| | - Wei-Ting Hsu
- Department
of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
- National
Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
- Research
Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
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4
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Liu H, Wu Y, Wu Z, Liu S, Zhang VL, Yu T. Coexisting Phases in Transition Metal Dichalcogenides: Overview, Synthesis, Applications, and Prospects. ACS NANO 2024; 18:2708-2729. [PMID: 38252696 DOI: 10.1021/acsnano.3c10665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Over the past decade, significant advancements have been made in phase engineering of two-dimensional transition metal dichalcogenides (TMDCs), thereby allowing controlled synthesis of various phases of TMDCs and facile conversion between them. Recently, there has been emerging interest in TMDC coexisting phases, which contain multiple phases within one nanostructured TMDC. By taking advantage of the merits from the component phases, the coexisting phases offer enhanced performance in many aspects compared with single-phase TMDCs. Herein, this review article thoroughly expounds the latest progress and ongoing efforts on the syntheses, properties, and applications of TMDC coexisting phases. The introduction section overviews the main phases of TMDCs (2H, 3R, 1T, 1T', 1Td), along with the advantages of phase coexistence. The subsequent section focuses on the synthesis methods for coexisting phases of TMDCs, with particular attention to local patterning and random formations. Furthermore, on the basis of the versatile properties of TMDC coexisting phases, their applications in magnetism, valleytronics, field-effect transistors, memristors, and catalysis are discussed. Lastly, a perspective is presented on the future development, challenges, and potential opportunities of TMDC coexisting phases. This review aims to provide insights into the phase engineering of 2D materials for both scientific and engineering communities and contribute to further advancements in this emerging field.
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Affiliation(s)
- Haiyang Liu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Yaping Wu
- School of Physics and Technology, Xiamen University, Xiamen 361005, China
| | - Zhiming Wu
- School of Physics and Technology, Xiamen University, Xiamen 361005, China
| | - Sheng Liu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Vanessa Li Zhang
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Ting Yu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
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5
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Zhang C, Gao Y, Zhang W, Zhang Z. Spatial Imaging and Control of Dark Excitons in Monolayer Transition Metal Dichalcogenides. NANO LETTERS 2023; 23:11424-11429. [PMID: 38009634 DOI: 10.1021/acs.nanolett.3c02590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Dark excitons play a vital role in exciton condensation and optical properties of monolayer transition metal dichalcogenides (MTMDs). Previous literature mainly focuses on the detection of the energy of the dark exciton, while spatial detection and control are equally important but are less studied. Here we report that for MTMD embedded in a semiconductor microcavity and under a uniform in-plane magnetic field the spatial distribution of the dark exciton can be probed by measuring that of the cavity photon for small exciton-exciton interaction energy. Further, we propose to realize the anomalous exciton Hall effect by exploiting spatially inhomogeneous coupling of the bright and dark excitons under a Gaussian excitation beam. This effect occurs regardless of the exciton-exciton interaction, which will strengthen the diffusion of excitons in the excitation region. These results provide an improved understanding of the excitons in MTMDs, thereby facilitating their potential practical applications.
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Affiliation(s)
- Chuanyi Zhang
- Henan Key Laboratory of Photovoltaic Materials and School of Future Technology, Henan University, Kaifeng 475004, China
- Joint Center for Theoretical Physics, Henan University, Kaifeng 475004, China
| | - Yang Gao
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
| | - Weifeng Zhang
- Henan Key Laboratory of Photovoltaic Materials and School of Future Technology, Henan University, Kaifeng 475004, China
- Institute of Quantum Materials and Physics, Henan Academy of Sciences, Zhengzhou 450046, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei 230026, China
- Hefei National Laboratory, University of Science and Technology of China, Hefei 230088, China
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6
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Chen H, Wang Q, Feng X, Wu W, Zhang L. Phonon Chirality Manipulation Mechanism in Transition-Metal Dichalcogenide Interlayer-Sliding Ferroelectrics. NANO LETTERS 2023. [PMID: 37976102 DOI: 10.1021/acs.nanolett.3c03787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
As an ideal platform, both the theoretical prediction and first experimental verification of chiral phonons are based on transition-metal dichalcogenide materials. The manipulation of phonon chirality in these materials will have a profound effect on the study of chiral phonons. In this work, we utilize the sliding ferroelectric effect to realize the phonon chirality manipulation mechanism in transition-metal dichalcogenide materials. Based on first-principles calculations, we find the different manipulation effects of interlayer sliding on the phonon chirality and Berry curvature in bilayer and four-layer MoS2 sliding ferroelectrics. These further affect the phonon angular momentum and magnetization under a temperature gradient and the phonon Hall effect under a magnetic field. Our work connects two emerging fields and opens up a new route to manipulating phonon chirality in transition-metal dichalcogenide materials through the sliding ferroelectric mechanism.
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Affiliation(s)
- Hao Chen
- Department of Physics, University of Science and Technology of China, Hefei 230026, China
- Phonon Engineering Research Center of Jiangsu Province, Center for Quantum Transport and Thermal Energy Science, Institute of Physics Frontiers and Interdisciplinary Sciences, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Qianqian Wang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Xukun Feng
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Weikang Wu
- Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061, China
| | - Lifa Zhang
- Phonon Engineering Research Center of Jiangsu Province, Center for Quantum Transport and Thermal Energy Science, Institute of Physics Frontiers and Interdisciplinary Sciences, School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
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7
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Mueller NS, Arul R, Kang G, Saunders AP, Johnson AC, Sánchez-Iglesias A, Hu S, Jakob LA, Bar-David J, de Nijs B, Liz-Marzán LM, Liu F, Baumberg JJ. Photoluminescence upconversion in monolayer WSe 2 activated by plasmonic cavities through resonant excitation of dark excitons. Nat Commun 2023; 14:5726. [PMID: 37714855 PMCID: PMC10504321 DOI: 10.1038/s41467-023-41401-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 09/04/2023] [Indexed: 09/17/2023] Open
Abstract
Anti-Stokes photoluminescence (PL) is light emission at a higher photon energy than the excitation, with applications in optical cooling, bioimaging, lasing, and quantum optics. Here, we show how plasmonic nano-cavities activate anti-Stokes PL in WSe2 monolayers through resonant excitation of a dark exciton at room temperature. The optical near-fields of the plasmonic cavities excite the out-of-plane transition dipole of the dark exciton, leading to light emission from the bright exciton at higher energy. Through statistical measurements on hundreds of plasmonic cavities, we show that coupling to the dark exciton leads to a near hundred-fold enhancement of the upconverted PL intensity. This is further corroborated by experiments in which the laser excitation wavelength is tuned across the dark exciton. We show that a precise nanoparticle geometry is key for a consistent enhancement, with decahedral nanoparticle shapes providing an efficient PL upconversion. Finally, we demonstrate a selective and reversible switching of the upconverted PL via electrochemical gating. Our work introduces the dark exciton as an excitation channel for anti-Stokes PL in WSe2 and paves the way for large-area substrates providing nanoscale optical cooling, anti-Stokes lasing, and radiative engineering of excitons.
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Affiliation(s)
- Niclas S Mueller
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK.
- Fritz Haber Institute of the Max Planck Society, 14195, Berlin, Germany.
| | - Rakesh Arul
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Gyeongwon Kang
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
- Department of Chemistry, Kangwon National University, Chuncheon, 24341, South Korea
| | - Ashley P Saunders
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Amalya C Johnson
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Ana Sánchez-Iglesias
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, Donostia-San Sebastián, 20014, Spain
- Centro de Física de Materiales, CSIC-UPV/EHU, Manuel Lardizabal Ibilbidea 5, Donostia-San Sebastián, 20018, Spain
| | - Shu Hu
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Lukas A Jakob
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Jonathan Bar-David
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Bart de Nijs
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK
| | - Luis M Liz-Marzán
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo de Miramón 194, Donostia-San Sebastián, 20014, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, 48009, Spain
- Centro de Investigación Biomédica en Red, Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Donostia-San Sebastián, 20014, Spain
| | - Fang Liu
- Department of Chemistry, Stanford University, Stanford, CA, 94305, USA
| | - Jeremy J Baumberg
- NanoPhotonics Centre, Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge, CB3 0HE, UK.
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8
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Cong X, Mohammadi PA, Zheng M, Watanabe K, Taniguchi T, Rhodes D, Zhang XX. Interplay of valley polarized dark trion and dark exciton-polaron in monolayer WSe 2. Nat Commun 2023; 14:5657. [PMID: 37704654 PMCID: PMC10500002 DOI: 10.1038/s41467-023-41475-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023] Open
Abstract
The interactions between charges and excitons involve complex many-body interactions at high densities. The exciton-polaron model has been adopted to understand the Fermi sea screening of charged excitons in monolayer transition metal dichalcogenides. The results provide good agreement with absorption measurements, which are dominated by dilute bright exciton responses. Here we investigate the Fermi sea dressing of spin-forbidden dark excitons in monolayer WSe2. With a Zeeman field, the valley-polarized dark excitons show distinct p-doping dependence in photoluminescence when the carriers reach a critical density. This density can be interpreted as the onset of strongly modified Fermi sea interactions and shifts with increasing exciton density. Through valley-selective excitation and dynamics measurements, we also infer an intervalley coupling between the dark trions and exciton-polarons mediated by the many-body interactions. Our results reveal the evolution of Fermi sea screening with increasing exciton density and the impacts of polaron-polaron interactions, which lay the foundation for understanding electronic correlations and many-body interactions in 2D systems.
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Affiliation(s)
- Xin Cong
- Department of Physics, University of Florida, Gainesville, FL, USA
| | | | - Mingyang Zheng
- Department of Physics, University of Florida, Gainesville, FL, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Japan
| | - Daniel Rhodes
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, USA
| | - Xiao-Xiao Zhang
- Department of Physics, University of Florida, Gainesville, FL, USA.
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9
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Ripin A, Peng R, Zhang X, Chakravarthi S, He M, Xu X, Fu KM, Cao T, Li M. Tunable phononic coupling in excitonic quantum emitters. NATURE NANOTECHNOLOGY 2023; 18:1020-1026. [PMID: 37264087 DOI: 10.1038/s41565-023-01410-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 04/28/2023] [Indexed: 06/03/2023]
Abstract
Engineering the coupling between fundamental quantum excitations is at the heart of quantum science and technologies. An outstanding case is the creation of quantum light sources in which coupling between single photons and phonons can be controlled and harnessed to enable quantum information transduction. Here we report the deterministic creation of quantum emitters featuring highly tunable coupling between excitons and phonons. The quantum emitters are formed in strain-induced quantum dots created in homobilayer WSe2. The colocalization of quantum-confined interlayer excitons and terahertz interlayer breathing-mode phonons, which directly modulates the exciton energy, leads to a uniquely strong phonon coupling to single-photon emission, with a Huang-Rhys factor reaching up to 6.3. The single-photon spectrum of interlayer exciton emission features a single-photon purity >83% and multiple phonon replicas, each heralding the creation of a phonon Fock state in the quantum emitter. Due to the vertical dipole moment of the interlayer exciton, the phonon-photon interaction is electrically tunable to be higher than the exciton and phonon decoherence rate, and hence promises to reach the strong-coupling regime. Our result demonstrates a solid-state quantum excitonic-optomechanical system at the atomic interface of the WSe2 bilayer that emits flying photonic qubits coupled with stationary phonons, which could be exploited for quantum transduction and interconnection.
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Affiliation(s)
- Adina Ripin
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Ruoming Peng
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA.
| | - Xiaowei Zhang
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | | | - Minhao He
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Xiaodong Xu
- Department of Physics, University of Washington, Seattle, WA, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Kai-Mei Fu
- Department of Physics, University of Washington, Seattle, WA, USA
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA
- Physical Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA
| | - Mo Li
- Department of Physics, University of Washington, Seattle, WA, USA.
- Department of Electrical and Computer Engineering, University of Washington, Seattle, WA, USA.
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10
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Zhang XW, Ren Y, Wang C, Cao T, Xiao D. Gate-Tunable Phonon Magnetic Moment in Bilayer Graphene. PHYSICAL REVIEW LETTERS 2023; 130:226302. [PMID: 37327431 DOI: 10.1103/physrevlett.130.226302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/27/2023] [Indexed: 06/18/2023]
Abstract
We develop a first-principles quantum scheme to calculate the phonon magnetic moment in solids. As a showcase example, we apply our method to study gated bilayer graphene, a material with strong covalent bonds. According to the classical theory based on the Born effective charge, the phonon magnetic moment in this system should vanish, yet our quantum mechanical calculations find significant phonon magnetic moments. Furthermore, the magnetic moment is highly tunable by changing the gate voltage. Our results firmly establish the necessity of the quantum mechanical treatment, and identify small-gap covalent materials as a promising platform for studying tunable phonon magnetic moment.
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Affiliation(s)
- Xiao-Wei Zhang
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Yafei Ren
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Chong Wang
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Di Xiao
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
- Department of Physics, University of Washington, Seattle, Washington 98195, USA
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11
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Wagner K, Iakovlev ZA, Ziegler JD, Cuccu M, Taniguchi T, Watanabe K, Glazov MM, Chernikov A. Diffusion of Excitons in a Two-Dimensional Fermi Sea of Free Charges. NANO LETTERS 2023. [PMID: 37220259 DOI: 10.1021/acs.nanolett.2c03796] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Propagation of light-emitting quasiparticles is of central importance across the fields of condensed matter physics and nanomaterials science. We experimentally demonstrate diffusion of excitons in the presence of a continuously tunable Fermi sea of free charge carriers in a monolayer semiconductor. Light emission from tightly bound exciton states in electrically gated WSe2 monolayer is detected using spatially and temporally resolved microscopy. The measurements reveal a nonmonotonic dependence of the exciton diffusion coefficient on the charge carrier density in both electron and hole doped regimes. Supported by analytical theory describing exciton-carrier interactions in a dissipative system, we identify distinct regimes of elastic scattering and quasiparticle formation determining exciton diffusion. The crossover region exhibits a highly unusual behavior of an increasing diffusion coefficient with increasing carrier densities. Temperature-dependent diffusion measurements further reveal characteristic signatures of freely propagating excitonic complexes dressed by free charges with effective mobilities up to 3 × 103 cm2/(V s).
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Affiliation(s)
- Koloman Wagner
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany
| | | | - Jonas D Ziegler
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Marzia Cuccu
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | | | - Alexey Chernikov
- Institute of Applied Physics and Wüzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
- Department of Physics, University of Regensburg, 93053 Regensburg, Germany
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12
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Bao X, Wu X, Ke Y, Wu K, Jiang C, Wu B, Li J, Yue S, Zhang S, Shi J, Du W, Zhong Y, Hu H, Bai P, Gong Y, Zhang Q, Zhang W, Liu X. Giant Out-of-Plane Exciton Emission Enhancement in Two-Dimensional Indium Selenide via a Plasmonic Nanocavity. NANO LETTERS 2023; 23:3716-3723. [PMID: 37125916 DOI: 10.1021/acs.nanolett.2c04902] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Out-of-plane (OP) exciton-based emitters in two-dimensional semiconductor materials are attractive candidates for novel photonic applications, such as radially polarized sources, integrated photonic chips, and quantum communications. However, their low quantum efficiency resulting from forbidden transitions limits their practicality. In this work, we achieve a giant enhancement of up to 34000 for OP exciton emission in indium selenide (InSe) via a designed Ag nanocube-over-Au film plasmonic nanocavity. The large photoluminescence enhancement factor (PLEF) is attributed to the induced OP local electric field (Ez) within the nanocavity, which facilitates effective OP exciton-plasmon interaction and subsequent tremendous enhancement. Moreover, the nanoantenna effect resulting from the effective interaction improves the directivity of spontaneous radiation. Our results not only reveal an effective photoluminescence enhancement approach for OP excitons but also present an avenue for designing on-chip photonic devices with an OP dipole orientation.
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Affiliation(s)
- Xiaotian Bao
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, People's Republic of China
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Xianxin Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yuxuan Ke
- School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Keming Wu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Chuanxiu Jiang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Bo Wu
- Guangdong Provincial Key Laboratory of Optical Information Materials and Technology & Institute of Electronic Paper Displays, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China
| | - Jing Li
- Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Shuai Yue
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Shuai Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Jianwei Shi
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Wenna Du
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Yangguang Zhong
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Huatian Hu
- Hubei Key Laboratory of Optical Information and Pattern Recognition, Wuhan Institute of Technology, Wuhan 430205, People's Republic of China
| | - Peng Bai
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - Yiyang Gong
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Qing Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, People's Republic of China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Center for Advanced Quantum Studies, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Xinfeng Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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13
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Liu J, Lu G, Zhang X. Exciton dispersion and exciton-phonon interaction in solids by time-dependent density functional theory. J Chem Phys 2023; 158:044116. [PMID: 36725491 DOI: 10.1063/5.0137326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Understanding, predicting, and ultimately controlling exciton band structure and exciton dynamics are central to diverse chemical and materials problems. Here, we have developed a first-principles method to determine exciton dispersion and exciton-phonon interaction in semiconducting and insulating solids based on time-dependent density functional theory. The first-principles method is formulated in planewave bases and pseudopotentials and can be used to compute exciton band structures, exciton charge density, ionic forces, the non-adiabatic coupling matrix between excitonic states, and the exciton-phonon coupling matrix. Based on the spinor formulation, the method enables self-consistent noncollinear calculations to capture spin-orbital coupling. Hybrid exchange-correlation functionals are incorporated to deal with long-range electron-hole interactions in solids. A sub-Hilbert space approximation is introduced to reduce the computational cost without loss of accuracy. For validations, we have applied the method to compute the exciton band structure and exciton-phonon coupling strength in transition metal dichalcogenide monolayers; both agree very well with the previous GW-Bethe-Salpeter equation and experimental results. This development paves the way for accurate determinations of exciton dynamics in a wide range of solid-state materials.
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Affiliation(s)
- Junyi Liu
- Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330, USA
| | - Gang Lu
- Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330, USA
| | - Xu Zhang
- Department of Physics and Astronomy, California State University Northridge, Northridge, California 91330, USA
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14
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Hasz K, Hu Z, Park KD, Raschke MB. Tip-Enhanced Dark Exciton Nanoimaging and Local Strain Control in Monolayer WSe 2. NANO LETTERS 2023; 23:198-204. [PMID: 36538369 DOI: 10.1021/acs.nanolett.2c03959] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Dark excitons in transition-metal dichalcogenides, with their long lifetimes and strong binding energies, provide potential platforms from photonic and optoelectronic applications to quantum information science even at room temperature. However, their spatial heterogeneity and sensitivity to strain is not yet understood. Here, we combine tip-enhanced photoluminescence spectroscopy with atomic force induced strain control to nanoimage dark excitons in WSe2 and their response to local strain. Dark exciton emission is facilitated by out-of-plane picocavity Purcell enhancement giving rise to spatially highly localized emission, providing for higher spatial resolution compared to bright exciton nanoimaging. Further, tip-antenna-induced dark exciton emission is enhanced in areas of higher strain associated with bubbles. In addition, active force control shows dark exciton emission to be more sensitive to strain with both compressive and tensile lattice deformation facilitating emission. This interplay between localized strain and Purcell effects provides novel pathways for nanomechanical exciton emission control.
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Affiliation(s)
- Kathryn Hasz
- Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States
- Department of Physics, Carthage College, Kenosha, Wisconsin 53140, United States
| | - Zuocheng Hu
- Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States
| | - Kyoung-Duck Park
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea
| | - Markus B Raschke
- Department of Physics and JILA, University of Colorado, Boulder, Colorado 80309, United States
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15
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Stevens CE, Chuang HJ, Rosenberger MR, McCreary KM, Dass CK, Jonker BT, Hendrickson JR. Enhancing the Purity of Deterministically Placed Quantum Emitters in Monolayer WSe 2. ACS NANO 2022; 16:20956-20963. [PMID: 36445838 DOI: 10.1021/acsnano.2c08553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We present a method utilizing an applied electrostatic potential for suppressing the broad defect bound excitonic emission in two-dimensional materials (2DMs) which otherwise inhibits the purity of strain induced single photon emitters (SPEs). Our heterostructure consists of a WSe2 monolayer on a polymer in which strain has been deterministically introduced via an atomic force microscope (AFM) tip. We show that by applying an electrostatic potential, the broad defect bound background is suppressed at cryogenic temperatures, resulting in a substantial improvement in single photon purity demonstrated by a 10-fold reduction of the correlation function g(2)(0) value from 0.73 to 0.07. In addition, we see a 2-fold increase in the intensity of the SPEs as well as the ability to activate/deactivate the emitters at certain wavelengths. Finally, we present an increase in the operating temperature of the SPE up to 110 K, a 50 K increase when compared with the results when no electrostatic potential is present.
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Affiliation(s)
| | - Hsun-Jen Chuang
- Materials Science & Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Matthew R Rosenberger
- Materials Science & Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Kathleen M McCreary
- Materials Science & Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Chandriker Kavir Dass
- Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
| | - Berend T Jonker
- Materials Science & Technology Division, Naval Research Laboratory, Washington, D.C. 20375, United States
| | - Joshua R Hendrickson
- Sensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433, United States
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16
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Shinokita K, Watanabe K, Taniguchi T, Matsuda K. Valley Relaxation of the Moiré Excitons in a WSe 2/MoSe 2 Heterobilayer. ACS NANO 2022; 16:16862-16868. [PMID: 36169188 DOI: 10.1021/acsnano.2c06813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The moiré superlattice consisting of lattice- or angular-mismatched van der Waals heterostructures drastically changes the physical properties of constituent atomically thin materials by confinement of the exciton by the moiré potential, which is promising for next-generation quantum optics. The moiré superlattice also affects the valley degrees of freedom of the monolayer transition-metal dichalcogenides (TMDs) and the valley-dependent optical selection rule, which results in the characteristic circular polarized light emission of the moiré exciton. However, the valley relaxation process of excitons in the moiré superlattice remains to be understood. Here, we studied valley relaxation of moiré excitons in a twisted WSe2/MoSe2 heterobilayer by circularly polarized photoluminescence and photoluminescence excitation (PLE) spectroscopy. The experimentally observed circularly polarized emission strongly depends on the excitation power density, which contrasts with the case of two-dimensional monolayer TMDs. The excitation power-dependent circularly polarized emission suggests the characteristic valley relaxation of the moiré exciton with a small density of states in zero-dimensional systems. In addition, the resonant PLE measurement reveals the intravalley relaxation process from the triplet to singlet state of the moiré exciton via Γ5 phonon emission. Our findings clarified the valley relaxation of the moiré excitons, which would lead to the application of the circularly polarized quantum light emitter in twisted semiconducting heterobilayers.
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Affiliation(s)
- Keisuke Shinokita
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Kazunari Matsuda
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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17
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Dai D, Wang X, Yang J, Dang J, Yuan Y, Fu B, Xie X, Yang L, Xiao S, Shi S, Yan S, Zhu R, Zuo Z, Wang C, Jin K, Gong Q, Xu X. Single charge control of localized excitons in heterostructures with ferroelectric thin films and two-dimensional transition metal dichalcogenides. NANOSCALE 2022; 14:14537-14543. [PMID: 36185039 DOI: 10.1039/d2nr04119g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Single charge control of localized excitons (LXs) in two-dimensional transition metal dichalcogenides (TMDCs) is crucial for potential applications in quantum information processing and storage. However, traditional electrostatic doping method by applying metallic gates onto TMDCs may cause inhomogeneous charge distribution, optical quenching, and energy loss. Herein, by locally controlling the ferroelectric polarization of the ferroelectric thin film BiFeO3 (BFO) with a scanning probe, we can deterministically manipulate the doping type of monolayer WSe2 to achieve p-type and n-type doping. This nonvolatile approach can maintain the doping type and hold the localized excitonic charges for a long time without applied voltage. Our work demonstrated that the ferroelectric polarization of BFO can control the charges of LXs effectively. Neutral and charged LXs have been observed in different ferroelectric polarization regions, confirmed by magnetic optical measurement. Highly circular polarization degree with 90% photon emission from these quantum emitters was achieved in high magnetic fields. Controlling the single charge of LXs in a non-volatile way shows a great potential for deterministic photon emission with desired charge states for photonic long-term memory.
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Affiliation(s)
- Danjie Dai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xinyan Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingnan Yang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China.
| | - Jianchen Dang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Yuan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bowen Fu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China.
| | - Xin Xie
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Longlong Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shan Xiao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shushu Shi
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sai Yan
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Zhu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhanchun Zuo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Can Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Kuijuan Jin
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
- CAS Center for Excellence in Topological Quantum Computation and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Qihuang Gong
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China.
| | - Xiulai Xu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, 100871 Beijing, China.
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18
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Kiriya D, Lien DH. Superacid Treatment on Transition Metal Dichalcogenides. NANO EXPRESS 2022. [DOI: 10.1088/2632-959x/ac87c2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Superacids are strong acids with an acidity higher than pure sulfuric acid. Recently, superacid treatment of monolayer transition metal dichalcogenide (TMDC) flakes, such as MoS2 and WS2, has shown a dramatic enhancement of optical properties, such as photoluminescence (PL) intensity. The superacid molecule is bis(trifluoromethane)sulfonimide (TFSI). In this review paper, we summarize and discuss the recent works and the current understanding of the TFSI treatment, and finally, we describe the outlook of the treatment on monolayer TMDCs.
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19
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Xu Y, Hu H, Chen W, Suo P, Zhang Y, Zhang S, Xu H. Phononic Cavity Optomechanics of Atomically Thin Crystal in Plasmonic Nanocavity. ACS NANO 2022; 16:12711-12719. [PMID: 35867404 DOI: 10.1021/acsnano.2c04478] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In the picture of molecular cavity optomechanics, surface-enhanced Raman scattering (SERS) can be understood as molecular oscillators parametrically coupled to plasmonic nanocavities supporting an extremely localized optical field. This enables SERS from conventional fingerprint detection toward quantum nanotechnologies associated with, e.g., frequency upconversion and optomechanically induced transparency. Here, we study a phononic cavity optomechanical system consisting of a monolayer MoS2 placed inside a plasmonic nanogap, where the coherent phonon-plasmon interaction involves the collective oscillation from tens of thousands of unit cells of the MoS2 crystal. We observe the selective nonlinear SERS enhancement of the system as determined by the laser-plasmon detuning, suggesting the dynamic backaction modification of the phonon populations. Anomalous superlinear power dependence of a second-order Raman-inactive phonon mode with respect to the first-order phonons is also observed, indicating the distinctive properties of the phononic nanodevice compared with the molecular system. Our results promote the development of robust phononic optomechanical nanocavities to further explore the related quantum correlation and nonlinear effects including parametric instabilities.
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Affiliation(s)
- Yuhao Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Huatian Hu
- The Institute for Advanced Studies, Wuhan University, Wuhan 430072, China
| | - Wen Chen
- Ecole Polytechnique Fédérale de Lausanne, Institute of Physics, Lausanne CH-1015, Switzerland
| | - Pengfei Suo
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
| | - Yuan Zhang
- Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, Key Laboratory of Material Physics, Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China
| | - Shunping Zhang
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
| | - Hongxing Xu
- School of Physics and Technology, Center for Nanoscience and Nanotechnology, and Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, Wuhan University, Wuhan 430072, China
- Wuhan Institute of Quantum Technology, Wuhan 430206, China
- School of Microelectronics, Wuhan University, Wuhan 430072, China
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20
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Kim G, Kim HM, Kumar P, Rahaman M, Stevens CE, Jeon J, Jo K, Kim KH, Trainor N, Zhu H, Sohn BH, Stach EA, Hendrickson JR, Glavin NR, Suh J, Redwing JM, Jariwala D. High-Density, Localized Quantum Emitters in Strained 2D Semiconductors. ACS NANO 2022; 16:9651-9659. [PMID: 35621266 DOI: 10.1021/acsnano.2c02974] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two-dimensional chalcogenide semiconductors have recently emerged as a host material for quantum emitters of single photons. While several reports on defect- and strain-induced single-photon emission from 2D chalcogenides exist, a bottom-up, lithography-free approach to producing a high density of emitters remains elusive. Further, the physical properties of quantum emission in the case of strained 2D semiconductors are far from being understood. Here, we demonstrate a bottom-up, scalable, and lithography-free approach for creating large areas of localized emitters with high density (∼150 emitters/um2) in a WSe2 monolayer. We induce strain inside the WSe2 monolayer with high spatial density by conformally placing the WSe2 monolayer over a uniform array of Pt nanoparticles with a size of 10 nm. Cryogenic, time-resolved, and gate-tunable luminescence measurements combined with near-field luminescence spectroscopy suggest the formation of localized states in strained regions that emit single photons with a high spatial density. Our approach of using a metal nanoparticle array to generate a high density of strained quantum emitters will be applied to scalable, tunable, and versatile quantum light sources.
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Affiliation(s)
- Gwangwoo Kim
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Hyong Min Kim
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Pawan Kumar
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Mahfujur Rahaman
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Christopher E Stevens
- Air Force Research Laboratory, Sensors Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
- KBR Inc., Beavercreek, Ohio 45431, United States
| | - Jonghyuk Jeon
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Kiyoung Jo
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Kwan-Ho Kim
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Nicholas Trainor
- 2D Crystal Consortium-Materials Innovation Platform, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Haoyue Zhu
- 2D Crystal Consortium-Materials Innovation Platform, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Byeong-Hyeok Sohn
- Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Eric A Stach
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Joshua R Hendrickson
- Air Force Research Laboratory, Sensors Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Nicholas R Glavin
- Air Force Research Laboratory, Materials and Manufacturing Directorate, Wright-Patterson Air Force Base, Ohio 45433, United States
| | - Joonki Suh
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea
| | - Joan M Redwing
- 2D Crystal Consortium-Materials Innovation Platform, Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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21
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Das S, Gupta G, Chatterjee S, Watanabe K, Taniguchi T, Majumdar K. Highly Nonlinear Biexcitonic Photocurrent from Ultrafast Interlayer Charge Transfer. ACS NANO 2022; 16:9728-9735. [PMID: 35604012 DOI: 10.1021/acsnano.2c03397] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Strong Coulomb interactions in monolayer semiconductors allow them to host optically active large many-body states, such as the five-particle state, charged biexciton. Strong nonlinear light absorption by the charged biexciton under spectral resonance, coupled with its charged nature, makes it intriguing for nonlinear photodetection─an area that is hitherto unexplored. Using the high built-in vertical electric field in an asymmetrically designed few-layer graphene encapsulated 1L-WS2 heterostructure, here we report a large, highly nonlinear photocurrent arising from the strong absorption by two charged biexciton species under zero external bias (self-powered mode). Time-resolved measurement reveals that the generated charged biexcitons transfer to the few-layer graphene in a time scale of sub-5 ps, indicating an ultrafast intrinsic limit of the photoresponse. By using single- and two-color photoluminescence excitation spectroscopy, we show that the two biexcitonic peaks originate from bright-dark and bright-bright exciton-trion combinations. Such innate nonlinearity in the photocurrent due to its biexcitonic origin, coupled with the ultrafast response due to swift interlayer charge transfer, exemplifies the promise of manipulating many-body effects in monolayers toward viable optoelectronic applications.
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Affiliation(s)
- Sarthak Das
- Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Garima Gupta
- Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Suman Chatterjee
- Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore 560012, India
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-044 Japan
| | - Kausik Majumdar
- Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore 560012, India
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22
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Bieniek M, Sadecka K, Szulakowska L, Hawrylak P. Theory of Excitons in Atomically Thin Semiconductors: Tight-Binding Approach. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1582. [PMID: 35564291 PMCID: PMC9104105 DOI: 10.3390/nano12091582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 02/01/2023]
Abstract
Atomically thin semiconductors from the transition metal dichalcogenide family are materials in which the optical response is dominated by strongly bound excitonic complexes. Here, we present a theory of excitons in two-dimensional semiconductors using a tight-binding model of the electronic structure. In the first part, we review extensive literature on 2D van der Waals materials, with particular focus on their optical response from both experimental and theoretical points of view. In the second part, we discuss our ab initio calculations of the electronic structure of MoS2, representative of a wide class of materials, and review our minimal tight-binding model, which reproduces low-energy physics around the Fermi level and, at the same time, allows for the understanding of their electronic structure. Next, we describe how electron-hole pair excitations from the mean-field-level ground state are constructed. The electron-electron interactions mix the electron-hole pair excitations, resulting in excitonic wave functions and energies obtained by solving the Bethe-Salpeter equation. This is enabled by the efficient computation of the Coulomb matrix elements optimized for two-dimensional crystals. Next, we discuss non-local screening in various geometries usually used in experiments. We conclude with a discussion of the fine structure and excited excitonic spectra. In particular, we discuss the effect of band nesting on the exciton fine structure; Coulomb interactions; and the topology of the wave functions, screening and dielectric environment. Finally, we follow by adding another layer and discuss excitons in heterostructures built from two-dimensional semiconductors.
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Affiliation(s)
- Maciej Bieniek
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany
| | - Katarzyna Sadecka
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Ludmiła Szulakowska
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
| | - Paweł Hawrylak
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
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23
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Zhang XW, Cao T. Ab initiocalculations of spin-nonconserving exciton-phonon scattering in monolayer transition metal dichalcogenides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:264002. [PMID: 35405669 DOI: 10.1088/1361-648x/ac6649] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 04/11/2022] [Indexed: 06/14/2023]
Abstract
We investigate the spin-nonconserving relaxation channel of excitons by their couplings with phonons in two-dimensional transition metal dichalcogenides usingab initioapproaches. Combining GW-Bethe-Salpeter equation method and density functional perturbation theory, we calculate the electron-phonon and exciton-phonon coupling matrix elements for the spin-flip scattering in monolayer WSe2, and further analyze the microscopic mechanisms influencing these scattering strengths. We find that phonons could produce effective in-plane magnetic fields which flip spin of excitons, giving rise to relaxation channels complimentary to the spin-conserving relaxation. Finally, we calculate temperature-dependent spin-flip exciton-phonon relaxation times. Our method and analysis can be generalized to study other two-dimensional materials and would stimulate experimental measurements of spin-flip exciton relaxation dynamics.
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Affiliation(s)
- Xiao-Wei Zhang
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, United States of America
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195, United States of America
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24
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Chand SB, Woods JM, Mejia E, Taniguchi T, Watanabe K, Grosso G. Visualization of Dark Excitons in Semiconductor Monolayers for High-Sensitivity Strain Sensing. NANO LETTERS 2022; 22:3087-3094. [PMID: 35290068 DOI: 10.1021/acs.nanolett.2c00436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Transition-metal dichalcogenides (TMDs) are layered materials that have a semiconducting phase with many advantageous optoelectronic properties, including tightly bound excitons and spin-valley locking. In tungsten-based TMDs, spin- and momentum-forbidden transitions give rise to dark excitons that typically are optically inaccessible but represent the lowest excitonic states of the system. Dark excitons can deeply affect the transport, dynamics, and coherence of bright excitons, hampering device performance. Therefore, it is crucial to create conditions in which these excitonic states can be visualized and controlled. Here, we show that compressive strain in WS2 enables phonon scattering of photoexcited electrons between momentum valleys, enhancing the formation of dark intervalley excitons. We show that the emission and spectral properties of momentum-forbidden excitons are accessible and strongly depend on the local strain environment that modifies the band alignment. This mechanism is further exploited for strain sensing in two-dimensional semiconductors, revealing a gauge factor exceeding 104.
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Affiliation(s)
- Saroj B Chand
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York 10031, New York, United States
| | - John M Woods
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York 10031, New York, United States
| | - Enrique Mejia
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York 10031, New York, United States
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Gabriele Grosso
- Photonics Initiative, Advanced Science Research Center, City University of New York, New York 10031, New York, United States
- Physics Program, Graduate Center, City University of New York, New York 10016, New York, United States
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25
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Wu Y, He J, Chen Y, Kong M, Zhang Y, Hu X, Lian J, Zhang H, Zhang R. Excellent response to near ultraviolet light and large intervalley scatterings of electrons in 2D SnS 2. NANOSCALE 2022; 14:5462-5471. [PMID: 35322849 DOI: 10.1039/d2nr00416j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Tin disulfide (SnS2) has attracted much attention as a novel two dimensional material due to its potential applications in electronics and optoelectronics. In this work, we investigated the optical properties of ultra-thin SnS2 film samples (∼8 nm) via spectroscopic ellipsometry, and found that SnS2 maintains a relatively high imaginary part of the dielectric constant (ε2) in the range of 256-377 nm indicating high optical response. The carrier transport properties of SnS2 were investigated considering full mode-resolved electron-phonon couplings, which reveal that the intervalley scatterings between degenerate valley (peaks) states via the fifth optical branch phonons play a dominant role in electron scattering, while ZA phonons dominate the hole scattering. The calculated electron mobility is ∼50 cm2 V-1 s-1 which is close to previously reported experimental results. By considering full el-ph interactions based on the rigid-band approximation, the maximum value of the thermoelectric figure of merit zT reaches 0.43 at 700 K. Our work not only reveals the promising applications of SnS2 in the fields of electronics and optoelectronics, but also showcases the computational framework for precise calculations of thermoelectric performances.
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Affiliation(s)
- Yu Wu
- Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Junbo He
- Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Ying Chen
- Department of Light Sources and Illuminating Engineering, Fudan University, Shanghai 200433, China
| | - Mingran Kong
- Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Yiming Zhang
- Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
| | - Xiaobing Hu
- Stare Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jianwei Lian
- Stare Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Hao Zhang
- Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
- Yiwu Research Institute of Fudan University, Chengbei Road, Yiwu City, Zhejiang 322000, China
- Nanjing University, National Laboratory of Solid State Microstructure, Nanjing 210093, China
| | - Rongjun Zhang
- Key Laboratory of Micro and Nano Photonic Structures (MOE) and Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China.
- Academy for Engineering & Technology, Fudan University, Shanghai, 200433, China.
- Yiwu Research Institute of Fudan University, Chengbei Road, Yiwu City, Zhejiang 322000, China
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26
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Altaiary MM, Liu E, Liang CT, Hsiao FC, van Baren J, Taniguchi T, Watanabe K, Gabor NM, Chang YC, Lui CH. Electrically Switchable Intervalley Excitons with Strong Two-Phonon Scattering in Bilayer WSe 2. NANO LETTERS 2022; 22:1829-1835. [PMID: 35201774 DOI: 10.1021/acs.nanolett.1c01590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We report the observation of QΓ intervalley exciton in bilayer WSe2 devices encapsulated by boron nitride. The QΓ exciton resides at ∼18 meV below the QK exciton. The QΓ and QK excitons exhibit different Stark shifts under an out-of-plane electric field due to their different interlayer dipole moments. By controlling the electric field, we can switch their energy ordering and control which exciton dominates the luminescence of bilayer WSe2. Remarkably, both QΓ and QK excitons exhibit unusually strong two-phonon replicas, which are comparable to or even stronger than the one-phonon replicas. By detailed theoretical simulation, we reveal the existence of numerous (≥14) two-phonon scattering paths involving (nearly) resonant exciton-phonon scattering in bilayer WSe2. To our knowledge, such electric-field-switchable intervalley excitons with strong two-phonon replicas have not been found in any other two-dimensional semiconductors. These make bilayer WSe2 a distinctive valleytronic material with potential novel applications.
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Affiliation(s)
- Mashael M Altaiary
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
- Department of Physics, University of Jeddah, Jeddah 23445, Saudi Arabia
| | - Erfu Liu
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
| | - Ching-Tarng Liang
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Fu-Chen Hsiao
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
- Advanced Semiconductor Device and Integration Laboratory, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Jeremiah van Baren
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Nathaniel M Gabor
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
- Canadian Institute for Advanced Research, 661 University Avenue, MaRS Centre West Tower, Toronto, Ontario M5G 1M1, Canada
| | - Yia-Chung Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Chun Hung Lui
- Department of Physics and Astronomy, University of California, Riverside, California 92521, United States
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27
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Mapara V, Barua A, Turkowski V, Trinh MT, Stevens C, Liu H, Nugera FA, Kapuruge N, Gutierrez HR, Liu F, Zhu X, Semenov D, McGill SA, Pradhan N, Hilton DJ, Karaiskaj D. Bright and Dark Exciton Coherent Coupling and Hybridization Enabled by External Magnetic Fields. NANO LETTERS 2022; 22:1680-1687. [PMID: 35129357 DOI: 10.1021/acs.nanolett.1c04667] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Magnetic field- and polarization-dependent measurements on bright and dark excitons in monolayer WSe2 combined with time-dependent density functional theory calculations reveal intriguing phenomena. Magnetic fields up to 25 T parallel to the WSe2 plane lead to a partial brightening of the energetically lower lying exciton, leading to an increase of the dephasing time. Using a broadband femtosecond pulse excitation, the bright and partially allowed excitonic state can be excited simultaneously, resulting in coherent quantum beating between these states. The magnetic fields perpendicular to the WSe2 plane energetically shift the bright and dark excitons relative to each other, resulting in the hybridization of the states at the K and K' valleys. Our experimental results are well captured by time-dependent density functional theory calculations. These observations show that magnetic fields can be used to control the coherent dephasing and coupling of the optical excitations in atomically thin semiconductors.
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Affiliation(s)
- Varun Mapara
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Arup Barua
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Volodymyr Turkowski
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - M Tuan Trinh
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Christopher Stevens
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Hengzhou Liu
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Florence A Nugera
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | - Nalaka Kapuruge
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
| | | | - Fang Liu
- Department of Chemistry, Stanford University, Stanford, California 94305, United States
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York, New York 10027-6902, United States
| | - Dmitry Semenov
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 30201, United States
| | - Stephen A McGill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 30201, United States
| | - Nihar Pradhan
- Layered Materials and Device Physics Laboratory, Department of Chemistry, Physics and Atmospheric Science, Jackson State University, Jackson, Mississippi 39217, United States
| | - David J Hilton
- Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, United States
| | - Denis Karaiskaj
- Department of Physics, University of South Florida, Tampa, Florida 33620, United States
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28
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Gelly RJ, Renaud D, Liao X, Pingault B, Bogdanovic S, Scuri G, Watanabe K, Taniguchi T, Urbaszek B, Park H, Lončar M. Probing dark exciton navigation through a local strain landscape in a WSe 2 monolayer. Nat Commun 2022; 13:232. [PMID: 35017506 PMCID: PMC8752834 DOI: 10.1038/s41467-021-27877-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 12/10/2021] [Indexed: 11/16/2022] Open
Abstract
In WSe2 monolayers, strain has been used to control the energy of excitons, induce funneling, and realize single-photon sources. Here, we developed a technique for probing the dynamics of free excitons in nanoscale strain landscapes in such monolayers. A nanosculpted tapered optical fiber is used to simultaneously generate strain and probe the near-field optical response of WSe2 monolayers at 5 K. When the monolayer is pushed by the fiber, its lowest energy states shift by as much as 390 meV (>20% of the bandgap of a WSe2 monolayer). Polarization and lifetime measurements of these red-shifting peaks indicate they originate from dark excitons. We conclude free dark excitons are funneled to high-strain regions during their long lifetime and are the principal participants in drift and diffusion at cryogenic temperatures. This insight supports proposals on the origin of single-photon sources in WSe2 and demonstrates a route towards exciton traps for exciton condensation. Here, the authors use a tapered optical fibre to create a dynamic, reversible strain in a suspended WSe2 monolayer, and observe that dark excitons are funnelled to high-strain regions and are the principal participants in drift and diffusion at cryogenic temperatures.
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Affiliation(s)
- Ryan J Gelly
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Dylan Renaud
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Xing Liao
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Benjamin Pingault
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Stefan Bogdanovic
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA
| | - Giovanni Scuri
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Bernhard Urbaszek
- Université de Toulouse, INSA-CNRS-UPS, LPCNO, 135 Avenue Rangueil, 31077, Toulouse, France
| | - Hongkun Park
- Department of Physics, Harvard University, Cambridge, MA, 02138, USA. .,Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.
| | - Marko Lončar
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA.
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29
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Jadczak J, Glazov M, Kutrowska-Girzycka J, Schindler JJ, Debus J, Ho CH, Watanabe K, Taniguchi T, Bayer M, Bryja L. Upconversion of Light into Bright Intravalley Excitons via Dark Intervalley Excitons in hBN-Encapsulated WSe 2 Monolayers. ACS NANO 2021; 15:19165-19174. [PMID: 34735768 PMCID: PMC8717626 DOI: 10.1021/acsnano.1c08286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 10/29/2021] [Indexed: 05/19/2023]
Abstract
Semiconducting monolayers of transition-metal dichalcogenides are outstanding platforms to study both electronic and phononic interactions as well as intra- and intervalley excitons and trions. These excitonic complexes are optically either active (bright) or inactive (dark) due to selection rules from spin or momentum conservation. Exploring ways of brightening dark excitons and trions has strongly been pursued in semiconductor physics. Here, we report on a mechanism in which a dark intervalley exciton upconverts light into a bright intravalley exciton in hBN-encapsulated WSe2 monolayers. Excitation spectra of upconverted photoluminescence reveals resonances at energies 34.5 and 46.0 meV below the neutral exciton in the nominal WSe2 transparency range. The required energy gains are theoretically explained by cooling of resident electrons or by exciton scattering with Λ- or K-valley phonons. Accordingly, an elevated temperature and a moderate concentration of resident electrons are necessary for observing the upconversion resonances. The interaction process observed between the inter- and intravalley excitons elucidates the importance of dark excitons for the optics of two-dimensional materials.
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Affiliation(s)
- Joanna Jadczak
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- (J.J.)
| | | | - Joanna Kutrowska-Girzycka
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | | | - Joerg Debus
- Experimental
Physics 2, TU Dortmund University, 44227 Dortmund, Germany
| | - Ching-Hwa Ho
- Graduate
Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 106, Taiwan
| | - Kenji Watanabe
- National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Manfred Bayer
- Experimental
Physics 2, TU Dortmund University, 44227 Dortmund, Germany
| | - Leszek Bryja
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- (L.B.)
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30
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Rosati R, Wagner K, Brem S, Perea-Causín R, Ziegler JD, Zipfel J, Taniguchi T, Watanabe K, Chernikov A, Malic E. Non-equilibrium diffusion of dark excitons in atomically thin semiconductors. NANOSCALE 2021; 13:19966-19972. [PMID: 34821228 DOI: 10.1039/d1nr06230a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Atomically thin semiconductors provide an excellent platform to study intriguing many-particle physics of tightly-bound excitons. In particular, the properties of tungsten-based transition metal dichalcogenides are determined by a complex manifold of bright and dark exciton states. While dark excitons are known to dominate the relaxation dynamics and low-temperature photoluminescence, their impact on the spatial propagation of excitons has remained elusive. In our joint theory-experiment study, we address this intriguing regime of dark state transport by resolving the spatio-temporal exciton dynamics in hBN-encapsulated WSe2 monolayers after resonant excitation. We find clear evidence of an unconventional, time-dependent diffusion during the first tens of picoseconds, exhibiting strong deviation from the steady-state propagation. Dark exciton states are initially populated by phonon emission from the bright states, resulting in creation of hot (unequilibrated) excitons whose rapid expansion leads to a transient increase of the diffusion coefficient by more than one order of magnitude. These findings are relevant for both fundamental understanding of the spatio-temporal exciton dynamics in atomically thin materials as well as their technological application by enabling rapid diffusion.
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Affiliation(s)
- Roberto Rosati
- Department of Physics, Philipps-Universität Marburg, Renthof 7, D-35032 Marburg, Germany.
| | - Koloman Wagner
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, Renthof 7, D-35032 Marburg, Germany.
| | - Raül Perea-Causín
- Chalmers University of Technology, Department of Physics, 412 96 Gothenburg, Sweden
| | - Jonas D Ziegler
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Jonas Zipfel
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Alexey Chernikov
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, Renthof 7, D-35032 Marburg, Germany.
- Chalmers University of Technology, Department of Physics, 412 96 Gothenburg, Sweden
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31
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Yuan L, Jeong J, Chi Kwock KW, Yanev ES, Grandel M, Rhodes DA, Luk TS, Schuck PJ, Yarotski D, Hone JC, Brener I, Prasankumar RP. Manipulation of Exciton Dynamics in Single-Layer WSe 2 Using a Toroidal Dielectric Metasurface. NANO LETTERS 2021; 21:9930-9938. [PMID: 34797671 DOI: 10.1021/acs.nanolett.1c03189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recent advances in emerging atomically thin transition metal dichalcogenide semiconductors with strong light-matter interactions and tunable optical properties provide novel approaches for realizing new material functionalities. Coupling two-dimensional semiconductors with all-dielectric resonant nanostructures represents an especially attractive opportunity for manipulating optical properties in both the near-field and far-field regimes. Here, by integrating single-layer WSe2 and titanium oxide (TiO2) dielectric metasurfaces with toroidal resonances, we realized robust exciton emission enhancement over 1 order of magnitude at both room and low temperatures. Furthermore, we could control exciton dynamics and annihilation by using temperature to tailor the spectral overlap of excitonic and toroidal resonances, allowing us to selectively enhance the Purcell effect. Our results provide rich physical insight into the strong light-matter interactions in single-layer TMDs coupled with toroidal dielectric metasurfaces, with important implications for optoelectronics and photonics applications.
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Affiliation(s)
- Long Yuan
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - Jeeyoon Jeong
- Department of Physics and Institute for Accelerator Science, Kangwon National University, 1 Gangwondaehak-gil, Chuncheon-si, Gangwon-do 24341, Korea
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Kevin Wen Chi Kwock
- Department of Electrical Engineering, Columbia University, New York, New York 10027, United States
| | - Emanuil S Yanev
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Michael Grandel
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Daniel A Rhodes
- Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Ting S Luk
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - P James Schuck
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Dmitry Yarotski
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
| | - James C Hone
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Igal Brener
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, United States
| | - Rohit P Prasankumar
- Center for Integrated Nanotechnologies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States
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32
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Dirnberger F, Ziegler JD, Faria Junior PE, Bushati R, Taniguchi T, Watanabe K, Fabian J, Bougeard D, Chernikov A, Menon VM. Quasi-1D exciton channels in strain-engineered 2D materials. SCIENCE ADVANCES 2021; 7:eabj3066. [PMID: 34714670 PMCID: PMC8555901 DOI: 10.1126/sciadv.abj3066] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/10/2021] [Indexed: 06/13/2023]
Abstract
Strain engineering is a powerful tool in designing artificial platforms for high-temperature excitonic quantum devices. Combining strong light-matter interaction with robust and mobile exciton quasiparticles, two-dimensional transition metal dichalcogenides (2D TMDCs) hold great promise in this endeavor. However, realizing complex excitonic architectures based on strain-induced electronic potentials alone has proven to be exceptionally difficult so far. Here, we demonstrate deterministic strain engineering of both single-particle electronic bandstructure and excitonic many-particle interactions. We create quasi-1D transport channels to confine excitons and simultaneously enhance their mobility through locally suppressed exciton-phonon scattering. Using ultrafast, all-optical injection and time-resolved readout, we realize highly directional exciton flow with up to 100% anisotropy both at cryogenic and room temperatures. The demonstrated fundamental modification of the exciton transport properties in a deterministically strained 2D material with effectively tunable dimensionality has broad implications for both basic solid-state science and emerging technologies.
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Affiliation(s)
- Florian Dirnberger
- Department of Physics, City College of New York, New York, NY 10031, USA
| | - Jonas D. Ziegler
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Paulo E. Faria Junior
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Rezlind Bushati
- Department of Physics, City College of New York, New York, NY 10031, USA
- Department of Physics, The Graduate Center, City University of New York, New York, NY 10016, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Jaroslav Fabian
- Institute for Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Dominique Bougeard
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Alexey Chernikov
- Department of Physics, University of Regensburg, 93040 Regensburg, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Dresden University of Technology, Dresden 01187, Germany
| | - Vinod M. Menon
- Department of Physics, City College of New York, New York, NY 10031, USA
- Department of Physics, The Graduate Center, City University of New York, New York, NY 10016, USA
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33
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Ren Y, Xiao C, Saparov D, Niu Q. Phonon Magnetic Moment from Electronic Topological Magnetization. PHYSICAL REVIEW LETTERS 2021; 127:186403. [PMID: 34767398 DOI: 10.1103/physrevlett.127.186403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
The traditional theory of magnetic moments for chiral phonons is based on the picture of the circular motion of the Born effective charge, typically yielding a small fractional value of the nuclear magneton. Here we investigate the adiabatic evolution of electronic states induced by the lattice vibration of a chiral phonon and obtain an electronic orbital magnetization in the form of a topological second Chern form. We find that the traditional theory needs to be refined by introducing a k resolved Born effective charge, and identify another contribution from the phonon-modified electronic energy together with the momentum-space Berry curvature. The second Chern form can diverge when there is a Yang's monopole near the parameter space of interest as illustrated by considering a phonon at the Brillouin zone corner in a gapped graphene model. We also find large magnetic moments for the optical phonon in bulk topological materials where nontopological contribution is also important. Our results agree with recent observations in experiments.
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Affiliation(s)
- Yafei Ren
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington 98195, USA
| | - Cong Xiao
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
- Department of Physics, The University of Hong Kong, Hong Kong, China
- HKU-UCAS Joint Institute of Theoretical and Computational Physics at Hong Kong, Hong Kong, China
| | - Daniyar Saparov
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Qian Niu
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
- ICQD/HFNL and School of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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34
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Li Z, Cordovilla Leon DF, Lee W, Datta K, Lyu Z, Hou J, Taniguchi T, Watanabe K, Kioupakis E, Deotare PB. Dielectric Engineering for Manipulating Exciton Transport in Semiconductor Monolayers. NANO LETTERS 2021; 21:8409-8417. [PMID: 34591493 DOI: 10.1021/acs.nanolett.1c02990] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The dielectric screening from the disordered media surrounding atomically thin transition metal dichalcogenides (TMDs) monolayers modifies the effective defect energy levels and thereby the transport and energy dynamics of excitons. In this work, we study this effect in WSe2 monolayers for different combinations of surrounding dielectric media. Specifically, we study the source of the anomalous diffusion of excitons in the WSe2 monolayer and attribute the anomaly to the modification of the energy distribution of defect states in different disordered dielectric environments. We use this insight to manipulate exciton transport by engineering the dielectric environment using a graphene/hexagonal boron nitride (h-BN) moiré superlattice. Finally, we observe that the effect of dielectric disorder is even more significant at high excitation fluences, contributing to the nonequilibrium phonon drag effect. These results provide an important step toward achieving control over the exciton energy transport for next-generation opto-excitonic devices.
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Affiliation(s)
- Zidong Li
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Darwin F Cordovilla Leon
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Woncheol Lee
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Kanak Datta
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhengyang Lyu
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jize Hou
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Emmanouil Kioupakis
- Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Parag B Deotare
- Electrical and Computer Engineering Department, University of Michigan, Ann Arbor, Michigan 48109, United States
- Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109, United States
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35
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Niu K, Weng M, Li S, Guo Z, Wang G, Han M, Pan F, Lin J. Direct Visualization of Large-Scale Intrinsic Atomic Lattice Structure and Its Collective Anisotropy in Air-Sensitive Monolayer 1T'- WTe 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2101563. [PMID: 34467674 PMCID: PMC8529427 DOI: 10.1002/advs.202101563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Probing large-scale intrinsic structure of air-sensitive 2D materials with atomic resolution is so far challenging due to their rapid oxidization and contamination. Here, by keeping the whole experiment including growth, transfer, and characterizations in an interconnected atmosphere-control environment, the large-scale intact lattice structure of air-sensitive monolayer 1T'-WTe2 is directly visualized by atom-resolved scanning transmission electron microscopy. Benefit from the large-scale atomic mapping, collective lattice distortions are further unveiled due to the presence of anisotropic rippling, which propagates perpendicular to only one of the preferential lattice planes in the same WTe2 monolayer. Such anisotropic lattice rippling modulates the intrinsic point defect (Te vacancy) distribution, in which they aggregate at the constrictive inner side of the undulating structure, presumably due to the ripple-induced asymmetric strain as elaborated by density functional theory. The results pave the way for atomic characterizations and defect engineering of air-sensitive 2D layered materials.
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Affiliation(s)
- Kangdi Niu
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and TechnologyShenzhen518055China
| | - Mouyi Weng
- School of Advanced MaterialsPeking UniversityShenzhen Graduate SchoolShenzhen518055China
| | - Songge Li
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
| | - Zenglong Guo
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
| | - Gang Wang
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
| | - Mengjiao Han
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and TechnologyShenzhen518055China
| | - Feng Pan
- School of Advanced MaterialsPeking UniversityShenzhen Graduate SchoolShenzhen518055China
| | - Junhao Lin
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and TechnologyShenzhen518055China
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36
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Wagner K, Zipfel J, Rosati R, Wietek E, Ziegler JD, Brem S, Perea-Causín R, Taniguchi T, Watanabe K, Glazov MM, Malic E, Chernikov A. Nonclassical Exciton Diffusion in Monolayer WSe_{2}. PHYSICAL REVIEW LETTERS 2021; 127:076801. [PMID: 34459627 DOI: 10.1103/physrevlett.127.076801] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
We experimentally demonstrate time-resolved exciton propagation in a monolayer semiconductor at cryogenic temperatures. Monitoring phonon-assisted recombination of dark states, we find a highly unusual case of exciton diffusion. While at 5 K the diffusivity is intrinsically limited by acoustic phonon scattering, we observe a pronounced decrease of the diffusion coefficient with increasing temperature, far below the activation threshold of higher-energy phonon modes. This behavior corresponds neither to well-known regimes of semiclassical free-particle transport nor to the thermally activated hopping in systems with strong localization. Its origin is discussed in the framework of both microscopic numerical and semiphenomenological analytical models illustrating the observed characteristics of nonclassical propagation. Challenging the established description of mobile excitons in monolayer semiconductors, these results open up avenues to study quantum transport phenomena for excitonic quasiparticles in atomically thin van der Waals materials and their heterostructures.
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Affiliation(s)
- Koloman Wagner
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
| | - Jonas Zipfel
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Roberto Rosati
- Department of Physics, Philipps-Universität Marburg, Renthof 7, Marburg D-35032, Germany
| | - Edith Wietek
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
| | - Jonas D Ziegler
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
| | - Samuel Brem
- Department of Physics, Philipps-Universität Marburg, Renthof 7, Marburg D-35032, Germany
| | - Raül Perea-Causín
- Department of Physics, Chalmers University of Technology, Fysikgården 1, 41258 Gothenburg, Sweden
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Ibaraki 305-004, Japan
| | | | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, Renthof 7, Marburg D-35032, Germany
- Department of Physics, Chalmers University of Technology, Fysikgården 1, 41258 Gothenburg, Sweden
| | - Alexey Chernikov
- Department of Physics, University of Regensburg, Regensburg D-93053, Germany
- Dresden Integrated Center for Applied Physics and Photonic Materials (IAPP) and Würzburg-Dresden Cluster of Excellence ct.qmat, Technische Universität Dresden, 01062 Dresden, Germany
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37
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Xie K, Li X, Cao T. Theory and Ab Initio Calculation of Optically Excited States-Recent Advances in 2D Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e1904306. [PMID: 31808581 DOI: 10.1002/adma.201904306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/19/2019] [Indexed: 05/16/2023]
Abstract
Recent studies of the optical properties of 2D materials have reported unique phenomena and features that are absent in conventional bulk semiconductors. Many of these interesting properties, such as enhanced light-matter coupling, gate-tunable photoluminescence, and unusual excitonic optical selection rules arise from the nature of the two- and multi-particle excited states such as strongly bound Wannier excitons and charged excitons. The theory, modeling, and ab initio calculations of these optically excited states in 2D materials are reviewed. Several analytical and ab initio approaches are introduced. These methods are compared with each other, revealing their relative strength and limitations. Recent works that apply these methods to a variety of 2D materials and material-defect systems are then highlighted. Understanding of the optically excited states in these systems is relevant not only for fundamental scientific research of electronic excitations and correlations, but also plays an important role in the future development of quantum information science and nano-photonics.
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Affiliation(s)
- Kaichen Xie
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Xiaosong Li
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Chemistry, University of Washington, Seattle, WA, 98195, USA
| | - Ting Cao
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, 98195, USA
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38
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Chen H, Wu W, Zhu J, Yang SA, Zhang L. Propagating Chiral Phonons in Three-Dimensional Materials. NANO LETTERS 2021; 21:3060-3065. [PMID: 33764075 DOI: 10.1021/acs.nanolett.1c00236] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Chiral phonons were initially proposed and experimentally verified in two-dimensional (2D) systems. Their intriguing effects have generated profound impacts on multiple research fields. However, all chiral phonons reported to date are constrained to be local, in the sense that their group velocities vanish identically. Here, we propose the concept of propagating 3D chiral phonons, which can transport the information on chirality and angular momentum. Guided by the necessary conditions and using first-principles calculations, we demonstrate their existence in WN2. The chirality, group velocity, and pseudoangular momentum are analyzed. Based on their selective coupling with valley electrons and photons, we propose an experimental setup to detect the unique feature of propagating chiral phonons. Our work endows chiral phonons with a crucial character-the ability to propagate and transport quantized information, which creates a new research direction and opens up the possibility to design novel phononic quantum devices.
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Affiliation(s)
- Hao Chen
- NNU-SULI Thermal Energy Research Center and Center for Quantum Transport and Thermal Energy Science (CQTES), School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
| | - Weikang Wu
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Jiaojiao Zhu
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372, Singapore
| | - Lifa Zhang
- NNU-SULI Thermal Energy Research Center and Center for Quantum Transport and Thermal Energy Science (CQTES), School of Physics and Technology, Nanjing Normal University, Nanjing 210023, China
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39
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Jiang Y, Chen S, Zheng W, Zheng B, Pan A. Interlayer exciton formation, relaxation, and transport in TMD van der Waals heterostructures. LIGHT, SCIENCE & APPLICATIONS 2021; 10:72. [PMID: 33811214 PMCID: PMC8018964 DOI: 10.1038/s41377-021-00500-1] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/08/2021] [Accepted: 02/24/2021] [Indexed: 05/06/2023]
Abstract
Van der Waals (vdW) heterostructures based on transition metal dichalcogenides (TMDs) generally possess a type-II band alignment that facilitates the formation of interlayer excitons between constituent monolayers. Manipulation of the interlayer excitons in TMD vdW heterostructures holds great promise for the development of excitonic integrated circuits that serve as the counterpart of electronic integrated circuits, which allows the photons and excitons to transform into each other and thus bridges optical communication and signal processing at the integrated circuit. As a consequence, numerous studies have been carried out to obtain deep insight into the physical properties of interlayer excitons, including revealing their ultrafast formation, long population recombination lifetimes, and intriguing spin-valley dynamics. These outstanding properties ensure interlayer excitons with good transport characteristics, and may pave the way for their potential applications in efficient excitonic devices based on TMD vdW heterostructures. At present, a systematic and comprehensive overview of interlayer exciton formation, relaxation, transport, and potential applications is still lacking. In this review, we give a comprehensive description and discussion of these frontier topics for interlayer excitons in TMD vdW heterostructures to provide valuable guidance for researchers in this field.
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Affiliation(s)
- Ying Jiang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
| | - Shula Chen
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China
| | - Weihao Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
| | - Biyuan Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, School of Physics and Electronics, and College of Materials Science and Engineering, Hunan University, Changsha, China.
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40
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Zinkiewicz M, Woźniak T, Kazimierczuk T, Kapuscinski P, Oreszczuk K, Grzeszczyk M, Bartoš M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Excitonic Complexes in n-Doped WS 2 Monolayer. NANO LETTERS 2021; 21:2519-2525. [PMID: 33683895 PMCID: PMC7995249 DOI: 10.1021/acs.nanolett.0c05021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/22/2021] [Indexed: 05/25/2023]
Abstract
We investigate the origin of emission lines apparent in the low-temperature photoluminescence spectra of n-doped WS2 monolayer embedded in hexagonal BN layers using external magnetic fields and first-principles calculations. Apart from the neutral A exciton line, all observed emission lines are related to the negatively charged excitons. Consequently, we identify emissions due to both the bright (singlet and triplet) and dark (spin- and momentum-forbidden) negative trions as well as the phonon replicas of the latter optically inactive complexes. The semidark trions and negative biexcitons are distinguished. On the basis of their experimentally extracted and theoretically calculated g-factors, we identify three distinct families of emissions due to exciton complexes in WS2: bright, intravalley, and intervalley dark. The g-factors of the spin-split subbands in both the conduction and valence bands are also determined.
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Affiliation(s)
- Małgorzata Zinkiewicz
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Tomasz Woźniak
- Department
of Semiconductor Materials Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego
27, 50-370 Wrocław, Poland
| | - Tomasz Kazimierczuk
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Piotr Kapuscinski
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wrocław, Poland
| | - Kacper Oreszczuk
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Magdalena Grzeszczyk
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Miroslav Bartoš
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
- Central
European Institute of Technology, Brno University
of Technology, Purkyňova
656/123, 612 00 Brno, Czech Republic
| | - Karol Nogajewski
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Clement Faugeras
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - Piotr Kossacki
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Marek Potemski
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - Adam Babiński
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Maciej R. Molas
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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41
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Li D, Trovatello C, Dal Conte S, Nuß M, Soavi G, Wang G, Ferrari AC, Cerullo G, Brixner T. Exciton-phonon coupling strength in single-layer MoSe 2 at room temperature. Nat Commun 2021; 12:954. [PMID: 33574235 PMCID: PMC7878916 DOI: 10.1038/s41467-021-20895-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/17/2020] [Indexed: 11/18/2022] Open
Abstract
Single-layer transition metal dichalcogenides are at the center of an ever increasing research effort both in terms of fundamental physics and applications. Exciton–phonon coupling plays a key role in determining the (opto)electronic properties of these materials. However, the exciton–phonon coupling strength has not been measured at room temperature. Here, we use two-dimensional micro-spectroscopy to determine exciton–phonon coupling of single-layer MoSe2. We detect beating signals as a function of waiting time induced by the coupling between A excitons and A′1 optical phonons. Analysis of beating maps combined with simulations provides the exciton–phonon coupling. We get a Huang–Rhys factor ~1, larger than in most other inorganic semiconductor nanostructures. Our technique offers a unique tool to measure exciton–phonon coupling also in other heterogeneous semiconducting systems, with a spatial resolution ~260 nm, and provides design-relevant parameters for the development of optoelectronic devices. The exciton–phonon coupling (EXPC) affects the opto-electronic properties of atomically thin semiconductors. Here, the authors develop two-dimensional micro-spectroscopy to determine the EXPC of monolayer MoSe2.
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Affiliation(s)
- Donghai Li
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Chiara Trovatello
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133, Milano, Italy
| | - Stefano Dal Conte
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133, Milano, Italy
| | - Matthias Nuß
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Giancarlo Soavi
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK.,Institute for Solid State Physics, Abbe Center of Photonics, Friedrich-Schiller-University Jena, Max-Wien-Platz 1, 07743, Jena, Germany
| | - Gang Wang
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, 9 JJ Thomson Avenue, Cambridge, CB3 0FA, UK.
| | - Giulio Cerullo
- Dipartimento di Fisica, Politecnico di Milano, Piazza L. da Vinci 32, I-20133, Milano, Italy. .,IFN-CNR, Piazza L. da Vinci 32, I-20133, Milano, Italy.
| | - Tobias Brixner
- Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany. .,Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074, Würzburg, Germany.
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42
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Affiliation(s)
- Meng Xing Na
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada.,Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Ziliang Ye
- Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1, Canada. .,Quantum Matter Institute, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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43
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Trivedi DB, Turgut G, Qin Y, Sayyad MY, Hajra D, Howell M, Liu L, Yang S, Patoary NH, Li H, Petrić MM, Meyer M, Kremser M, Barbone M, Soavi G, Stier AV, Müller K, Yang S, Esqueda IS, Zhuang H, Finley JJ, Tongay S. Room-Temperature Synthesis of 2D Janus Crystals and their Heterostructures. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e2006320. [PMID: 33175433 DOI: 10.1002/adma.202006320] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/14/2020] [Indexed: 06/11/2023]
Abstract
Janus crystals represent an exciting class of 2D materials with different atomic species on their upper and lower facets. Theories have predicted that this symmetry breaking induces an electric field and leads to a wealth of novel properties, such as large Rashba spin-orbit coupling and formation of strongly correlated electronic states. Monolayer MoSSe Janus crystals have been synthesized by two methods, via controlled sulfurization of monolayer MoSe2 and via plasma stripping followed thermal annealing of MoS2 . However, the high processing temperatures prevent growth of other Janus materials and their heterostructures. Here, a room-temperature technique for the synthesis of a variety of Janus monolayers with high structural and optical quality is reported. This process involves low-energy reactive radical precursors, which enables selective removal and replacement of the uppermost chalcogen layer, thus transforming classical transition metal dichalcogenides into a Janus structure. The resulting materials show clear mixed character for their excitonic transitions, and more importantly, the presented room-temperature method enables the demonstration of first vertical and lateral heterojunctions of 2D Janus TMDs. The results present significant and pioneering advances in the synthesis of new classes of 2D materials, and pave the way for the creation of heterostructures from 2D Janus layers.
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Affiliation(s)
- Dipesh B Trivedi
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Guven Turgut
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Ying Qin
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Mohammed Y Sayyad
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Debarati Hajra
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Madeleine Howell
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Lei Liu
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Sijie Yang
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Naim Hossain Patoary
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Han Li
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Marko M Petrić
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Moritz Meyer
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Malte Kremser
- Walter Schottky Institut, Physik Department and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Matteo Barbone
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Giancarlo Soavi
- Institut für Festkörperphysik, Friedrich-Schiller-Universität Jena, Max-Wien-Platz 1, Jena, 07743, Germany
| | - Andreas V Stier
- Walter Schottky Institut, Physik Department and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Kai Müller
- Walter Schottky Institut, Department of Electrical and Computer Engineering and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Shize Yang
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Ivan Sanchez Esqueda
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Houlong Zhuang
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
| | - Jonathan J Finley
- Walter Schottky Institut, Physik Department and MCQST, Technische Universität München, Am Coulombwall 4, Garching, 85748, Germany
| | - Sefaattin Tongay
- School of Electrical, Computer, and Energy Engineering, Arizona State University, Tempe, AZ, 85287, USA
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44
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Wang T, Li Z, Li Y, Lu Z, Miao S, Lian Z, Meng Y, Blei M, Taniguchi T, Watanabe K, Tongay S, Smirnov D, Zhang C, Shi SF. Giant Valley-Polarized Rydberg Excitons in Monolayer WSe 2 Revealed by Magneto-photocurrent Spectroscopy. NANO LETTERS 2020; 20:7635-7641. [PMID: 32902286 DOI: 10.1021/acs.nanolett.0c03167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A strong Coulomb interaction could lead to a strongly bound exciton with high-order excited states, similar to the Rydberg atom. The interaction of giant Rydberg excitons can be engineered for a correlated ordered exciton array with a Rydberg blockade, which is promising for realizing quantum simulation. Monolayer transition metal dichalcogenides, with their greatly enhanced Coulomb interaction, are an ideal platform to host the Rydberg excitons in two dimensions. Here, we employ helicity-resolved magneto-photocurrent spectroscopy to identify Rydberg exciton states up to 11s in monolayer WSe2. Notably, the radius of the Rydberg exciton at 11s can be as large as 214 nm, orders of magnitude larger than the 1s exciton. The giant valley-polarized Rydberg exciton not only provides an exciting platform to study the strong exciton-exciton interaction and nonlinear exciton response but also allows the investigation of the different interplay between the Coulomb interaction and Landau quantization, tunable from a low- to high-magnetic-field limit.
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Affiliation(s)
- Tianmeng Wang
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Zhipeng Li
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Yunmei Li
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Zhengguang Lu
- National High Magnetic Field Lab, Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Shengnan Miao
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Zhen Lian
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Yuze Meng
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mark Blei
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Takashi Taniguchi
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Dmitry Smirnov
- National High Magnetic Field Lab, Tallahassee, Florida 32310, United States
| | - Chuanwei Zhang
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Su-Fei Shi
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Department of Electrical, Computer & Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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45
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Rossi D, Liu X, Lee Y, Khurana M, Puthenpurayil J, Kim K, Akimov AV, Cheon J, Son DH. Intense Dark Exciton Emission from Strongly Quantum-Confined CsPbBr 3 Nanocrystals. NANO LETTERS 2020; 20:7321-7326. [PMID: 32845638 DOI: 10.1021/acs.nanolett.0c02714] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Dark exciton as the lowest-energy (ground) exciton state in metal halide perovskite nanocrystals is a subject of much interest. This is because the superior performance of perovskites as the photon source combined with long lifetime of dark exciton can be attractive for many applications of exciton. However, the direct observation of the intense and long-lived dark exciton emission, indicating facile access to dark ground exciton state, has remained elusive. Here, we report the intense photoluminescence from dark exciton with microsecond lifetime in strongly confined CsPbBr3 nanocrystals and reveal the crucial role of confinement in accessing the dark ground exciton state. This study establishes the potential of strongly quantum-confined perovskite nanostructures as the excellent platform to harvest the benefits of extremely long-lived dark exciton.
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Affiliation(s)
- Daniel Rossi
- Center for NanoMedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
| | - Xiaohan Liu
- Department of Physics, Texas A&M University, College Station, Texas 777843, United States
| | - Yangjin Lee
- Center for NanoMedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Mohit Khurana
- Department of Physics, Texas A&M University, College Station, Texas 777843, United States
| | - Joseph Puthenpurayil
- Department of Chemistry, Texas A&M University, College Station, Texas 777843, United States
| | - Kwanpyo Kim
- Center for NanoMedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Alexey V Akimov
- Department of Physics, Texas A&M University, College Station, Texas 777843, United States
- Russian Quantum Center, Skolkovo, Moscow 143025, Russia
- PN Lebedev Institute RAS, Moscow 119991, Russia
| | - Jinwoo Cheon
- Center for NanoMedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
- Graduate Program of Nano Biomedical Engineering (BME), Advanced Science Institute, Yonsei University, Seoul 03722, Republic of Korea
| | - Dong Hee Son
- Center for NanoMedicine, Institute for Basic Science (IBS), Seoul 03722, Republic of Korea
- Department of Chemistry, Texas A&M University, College Station, Texas 777843, United States
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46
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Zinkiewicz M, Slobodeniuk AO, Kazimierczuk T, Kapuściński P, Oreszczuk K, Grzeszczyk M, Bartos M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Neutral and charged dark excitons in monolayer WS 2. NANOSCALE 2020; 12:18153-18159. [PMID: 32853305 DOI: 10.1039/d0nr04243a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies on WSe2, we identify the Coulomb exchange interaction coupled neutral dark and grey excitons through their polarization properties, while an analogous effect is not observed for dark trions. Applying the magnetic field in both perpendicular and parallel configurations with respect to the monolayer plane, we determine the g-factor of dark trions to be g ∼ -8.6. Their decay rate is close to 0.5 ns, more than 2 orders of magnitude longer than that of bright excitons.
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Affiliation(s)
- M Zinkiewicz
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - A O Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, Praha 2 CZ-121 16, Czech Republic
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - P Kapuściński
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, ul. Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - K Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech Republic
| | - K Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland. and Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - A Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
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47
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Exciton g-factors in monolayer and bilayer WSe 2 from experiment and theory. Nat Commun 2020; 11:4539. [PMID: 32913234 PMCID: PMC7483470 DOI: 10.1038/s41467-020-18019-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 07/28/2020] [Indexed: 11/08/2022] Open
Abstract
The optical properties of monolayer and bilayer transition metal dichalcogenide semiconductors are governed by excitons in different spin and valley configurations, providing versatile aspects for van der Waals heterostructures and devices. Here, we present experimental and theoretical studies of exciton energy splittings in external magnetic field in neutral and charged WSe2 monolayer and bilayer crystals embedded in a field effect device for active doping control. We develop theoretical methods to calculate the exciton g-factors from first principles for all possible spin-valley configurations of excitons in monolayer and bilayer WSe2 including valley-indirect excitons. Our theoretical and experimental findings shed light on some of the characteristic photoluminescence peaks observed for monolayer and bilayer WSe2. In more general terms, the theoretical aspects of our work provide additional means for the characterization of single and few-layer transition metal dichalcogenides, as well as their heterostructures, in the presence of external magnetic fields.
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48
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Wang J, Li H, Ma Y, Zhao M, Liu W, Wang B, Wu S, Liu X, Shi L, Jiang T, Zi J. Routing valley exciton emission of a WS 2 monolayer via delocalized Bloch modes of in-plane inversion-symmetry-broken photonic crystal slabs. LIGHT, SCIENCE & APPLICATIONS 2020; 9:148. [PMID: 32884677 PMCID: PMC7442784 DOI: 10.1038/s41377-020-00387-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/03/2020] [Accepted: 08/11/2020] [Indexed: 05/05/2023]
Abstract
The valleys of two-dimensional transition metal dichalcogenides (TMDCs) offer a new degree of freedom for information processing. To take advantage of this valley degree of freedom, on the one hand, it is feasible to control valleys by utilizing different external stimuli, such as optical and electric fields. On the other hand, nanostructures are also used to separate the valleys by near-field coupling. However, for both of the above methods, either the required low-temperature environment or low degree of coherence properties limit their further applications. Here, we demonstrate that all-dielectric photonic crystal (PhC) slabs without in-plane inversion symmetry (C2 symmetry) can separate and route valley exciton emission of a WS2 monolayer at room temperature. Coupling with circularly polarized photonic Bloch modes of such PhC slabs, valley photons emitted by a WS2 monolayer are routed directionally and are efficiently separated in the far field. In addition, far-field emissions are directionally enhanced and have long-distance spatial coherence properties.
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Affiliation(s)
- Jiajun Wang
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
| | - Han Li
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, 410073 Changsha, China
| | - Yating Ma
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, 410073 Changsha, China
| | - Maoxiong Zhao
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
| | - Wenzhe Liu
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
| | - Bo Wang
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
| | - Shiwei Wu
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093 Nanjing, China
| | - Xiaohan Liu
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093 Nanjing, China
| | - Lei Shi
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093 Nanjing, China
| | - Tian Jiang
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, 410073 Changsha, China
| | - Jian Zi
- State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonics Structures (Ministry of Education) and Department of Physics, Fudan University, 200433 Shanghai, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093 Nanjing, China
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49
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Lan T, Ding B, Liu B. Magneto‐optic effect of two‐dimensional materials and related applications. NANO SELECT 2020. [DOI: 10.1002/nano.202000032] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Tianshu Lan
- Tsinghua‐Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China
| | - Baofu Ding
- Tsinghua‐Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China
| | - Bilu Liu
- Tsinghua‐Berkeley Shenzhen Institute and Tsinghua Shenzhen International Graduate School Tsinghua University Shenzhen 518055 China
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50
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Li Z, Wang T, Miao S, Li Y, Lu Z, Jin C, Lian Z, Meng Y, Blei M, Taniguchi T, Watanabe K, Tongay S, Yao W, Smirnov D, Zhang C, Shi SF. Phonon-exciton Interactions in WSe 2 under a quantizing magnetic field. Nat Commun 2020; 11:3104. [PMID: 32561746 PMCID: PMC7305315 DOI: 10.1038/s41467-020-16934-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/28/2020] [Indexed: 11/16/2022] Open
Abstract
Strong many-body interaction in two-dimensional transitional metal dichalcogenides provides a unique platform to study the interplay between different quasiparticles, such as prominent phonon replica emission and modified valley-selection rules. A large out-of-plane magnetic field is expected to modify the exciton-phonon interactions by quantizing excitons into discrete Landau levels, which is largely unexplored. Here, we observe the Landau levels originating from phonon-exciton complexes and directly probe exciton-phonon interaction under a quantizing magnetic field. Phonon-exciton interaction lifts the inter-Landau-level transition selection rules for dark trions, manifested by a distinctively different Landau fan pattern compared to bright trions. This allows us to experimentally extract the effective mass of both holes and electrons. The onset of Landau quantization coincides with a significant increase of the valley-Zeeman shift, suggesting strong many-body effects on the phonon-exciton interaction. Our work demonstrates monolayer WSe2 as an intriguing playground to study phonon-exciton interactions and their interplay with charge, spin, and valley.
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Affiliation(s)
- Zhipeng Li
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Tianmeng Wang
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Shengnan Miao
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Yunmei Li
- Department of Physics, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Zhenguang Lu
- National High Magnetic Field Lab, Tallahassee, FL, 32310, USA
- Department of Physics, Florida State University, Tallahassee, FL, 32306, USA
| | - Chenhao Jin
- Kavli Institute, Cornell University, Ithaca, NY, 14853, USA
| | - Zhen Lian
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Yuze Meng
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA
| | - Mark Blei
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - Takashi Taniguchi
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, AZ, 85287, USA
| | - Wang Yao
- Department of Physics, University of Hong Kong, Hong Kong, China
| | - Dmitry Smirnov
- National High Magnetic Field Lab, Tallahassee, FL, 32310, USA
| | - Chuanwei Zhang
- Department of Physics, The University of Texas at Dallas, Richardson, TX, 75080, USA
| | - Su-Fei Shi
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
- Department of Electrical, Computer & Systems Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
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