1
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Liu Y, Liu H, Qin F, Yang A, Liu S, Zhang L, Zeng M, Wang J, Fu L, Lv R, Zhang K, Wu F, Wang H, Yu T. Electrically Pumped Valley Emitter in Transition Metal Dichalcogenides with Magnetic Manipulation. SMALL METHODS 2025:e2500156. [PMID: 40420648 DOI: 10.1002/smtd.202500156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2025] [Revised: 05/10/2025] [Indexed: 05/28/2025]
Abstract
Optical pumping has been extensively employed as a straightforward and efficient method for the investigation of excitonic effects in 2D transition metal dichalcogenides (TMDCs). However, the challenge of achieving well-matched resonant excitation makes it difficult to conduct a comprehensive and rigorous comparative study across different TMDCs systems. In this work, electrical pumping is utilized on quantum well structures of TMDCs, enabling equivalent carrier injection with similar kinetic energy while effectively mitigating the effects of non-resonant excitation. Valley-polarized electroluminescence (VP-EL) is systematically investigated under varying magnetic fields, demonstrating that without magnetic electrodes or substrates, reversing the magnetic field direction induces a corresponding reversal in the EL valley polarization. A comparative analysis of VP-EL from monolayer WS2, its homobilayer (WS2/WS2), and heterobilayer (WS2/WSe2) reveals that large spin-orbit coupling (SOC) and dark exciton ground state of WS2 enable the polarization reversal tunable by interlayer charge transfer and spin-matched interlayer hopping. This work elucidates the roles of SOC and the excitonic states for magneto-electroluminescence and demonstrates electrical pumping as a vital technique for the exploration of optical properties of 2D semiconductors.
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Affiliation(s)
- Yilin Liu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Haiyang Liu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Fanglu Qin
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Aosai Yang
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Sheng Liu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Li Zhang
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Mengqi Zeng
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Junyong Wang
- CAS Key Laboratory of Nanophotonic Materials and Devices and Key Laboratory of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou, 215123, China
| | - Lei Fu
- College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Ruitao Lv
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
- Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Kai Zhang
- CAS Key Laboratory of Nanophotonic Materials and Devices and Key Laboratory of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou, 215123, China
| | - Fengcheng Wu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Hao Wang
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
| | - Ting Yu
- School of Physics and Technology, Wuhan University, Wuhan, 430072, China
- Wuhan Institute of Quantum Technology, Wuhan, 430206, China
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2
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Kim H, Wang H, Wang Y, Shinokita K, Watanabe K, Taniguchi T, Konabe S, Matsuda K. Identification of Two-Dimensional Interlayer Excitons and Their Valley Polarization in MoSe 2/WSe 2 Heterostructure with h-BN Spacer Layer. ACS NANO 2025; 19:322-330. [PMID: 39810375 DOI: 10.1021/acsnano.4c05963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2025]
Abstract
Interlayer excitons (IXs) in the heterostructure of monolayer transition metal dichalcogenides (TMDs) are considered as a promising platform to study fundamental exciton physics and for potential applications of next generation optoelectronic devices. The IXs trapped in the moiré potential in a twisted monolayer TMD heterostructure such as MoSe2/WSe2 form zero-dimensional (0D) moiré excitons. Introducing an atomically thin insulating layer between TMD monolayers in a twisted heterostructure would modulate the moiré potential landscape, thereby tuning 0D IXs into 2D IXs. However, the optical characteristics of IXs have not been elucidated. Here, we have experimentally investigated the significant optical characteristics arising from IXs in a MoSe2/h-BN/WSe2 heterostructure by optical spectroscopy. The experimental results of time-resolved photoluminescence spectroscopy combined with phenomenological rate equation analysis reveal that the radiative decay rate of IXs in the MoSe2/h-BN/WSe2 heterostructure changes as a function of temperature, which strongly suggests the emergence of 2D IXs by the modulation of potential. Moreover, we demonstrate the valley polarization arising from the prolonged valley relaxation lifetime of 2D IXs reaching 100 ns at low temperature, which is dominated by electron-hole exchange interactions. These findings provide us with an effective strategy to tailor the dimensionality of IXs and elucidate the desired optoelectronic response of IXs in monolayer semiconductor heterostructures.
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Affiliation(s)
- Heejun Kim
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Haonan Wang
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Yanlin Wang
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Keisuke Shinokita
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Satoru Konabe
- Department of Chemical Science and Technology, Hosei University, 3-7-2 Kajinocho, Koganei, Tokyo 184-8584, Japan
| | - Kazunari Matsuda
- Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011, Japan
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3
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Cutshall J, Mahdikhany F, Roche A, Shanks DN, Koehler MR, Mandrus DG, Taniguchi T, Watanabe K, Zhu Q, LeRoy BJ, Schaibley JR. Imaging interlayer exciton superfluidity in a 2D semiconductor heterostructure. SCIENCE ADVANCES 2025; 11:eadr1772. [PMID: 39752490 PMCID: PMC11698081 DOI: 10.1126/sciadv.adr1772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 11/27/2024] [Indexed: 01/06/2025]
Abstract
Excitons, which are Coulomb bound electron-hole pairs, are composite bosons and thus at low temperature can form a superfluid state with a single well-defined amplitude and phase. We directly image this macroscopic exciton superfluid state in an hBN-separated MoSe2-WSe2 heterostructure. At high density, we identify quasi-long-range order over the entire active area of our sample, through spatially resolved coherence measurements. By varying the exciton density and sample temperature, we map out the phase diagram of the superfluid. We observe the superfluid phase persisting to a temperature of 15 K, which is in excellent agreement with theoretical predictions. This works paves the way to realizing on chip superfluid structures capable of studying fundamental physical behaviors and quantum devices that use superfluidity.
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Affiliation(s)
- Jacob Cutshall
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
| | - Fateme Mahdikhany
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
- McCormick School of Engineering, Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Anna Roche
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
| | - Daniel N. Shanks
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
| | - Michael R. Koehler
- IAMM Diffraction Facility, Institute for Advanced Materials and Manufacturing, University of Tennessee, Knoxville, TN 37920, USA
| | - David G. Mandrus
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Physics and Astronomy, University of Tennessee, Knoxville, TN 37996, USA
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Qizhong Zhu
- Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter, Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics, South China Normal University, Guangzhou 510006, China
- Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics, South China Normal University, Guangzhou 510006, China
| | - Brian J. LeRoy
- Department of Physics, University of Arizona, Tucson, AZ 85721, USA
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4
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Li W, Qin Q, Li X, Huangfu Y, Shen D, Liu J, Li J, Li B, Wu R, Duan X. Robust Growth of 2D Transition Metal Dichalcogenide Vertical Heterostructures via Ammonium-Assisted CVD Strategy. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2408367. [PMID: 39300853 DOI: 10.1002/adma.202408367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 08/20/2024] [Indexed: 09/22/2024]
Abstract
Two dimension (2D) transition metal dichalcogenides (TMD) heterostructures have opened unparalleled prospects for next-generation electronic and optoelectronic applications due to their atomic-scale thickness and distinct physical properties. The chemical vapor deposition (CVD) method is the most feasible approach to prepare 2D TMD heterostructures. However, the synthesis of 2D vertical heterostructures faces competition between in-plane and out-of-plane growth, which makes it difficult to precisely control the growth of vertical heterostructures. Here, a universal and controllable strategy is reported to grow various 2D TMD vertical heterostructures through an ammonium-assisted CVD process. The ammonium-assisted strategy shows excellent controllability and operational simplicity to prevent interlayer diffusion/alloying and thermal decomposition of the existed TMD templates. Ab initio simulations demonstrate that the reaction between NH4Cl and MoS2 leads to the formation of MoS3 clusters, promoting the nucleation and growth of 2D MoS2 on existed 2D WS2 layer, thereby leading to the growth of vertical heterostructure. The resulting 2D WSe2/WS2 vertical heterostructure photodetectors demonstrate an outstanding optoelectronic performance, which are comparable to the performances of photodetectors fabricated from mechanically exfoliated and stacked vertical heterostructures. The ammonium-assisted strategy for robust growth of high-quality vertical van der Waals heterostructures will facilitate fundamental physics investigations and device applications in electronics and optoelectronics.
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Affiliation(s)
- Wei Li
- College of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Qiuyin Qin
- Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Xin Li
- Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Ying Huangfu
- Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Dingyi Shen
- Hubei Key Laboratory of Energy Storage and Power Battery, School of Mathematics, Physics and Optoelectronic Engineering, Hubei University of Automotive Technology, Shiyan, 442002, China
| | - Jialing Liu
- Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Jia Li
- Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
| | - Bo Li
- College of Semiconductors (College of Integrated Circuits), Hunan University, Changsha, 410082, China
| | - Ruixia Wu
- College of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Xidong Duan
- Hunan Key Laboratory of Two-Dimensional Materials, State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China
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5
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Blundo E, Tuzi F, Cianci S, Cuccu M, Olkowska-Pucko K, Kipczak Ł, Contestabile G, Miriametro A, Felici M, Pettinari G, Taniguchi T, Watanabe K, Babiński A, Molas MR, Polimeni A. Localisation-to-delocalisation transition of moiré excitons in WSe 2/MoSe 2 heterostructures. Nat Commun 2024; 15:1057. [PMID: 38316753 PMCID: PMC10844653 DOI: 10.1038/s41467-024-44739-9] [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: 04/24/2023] [Accepted: 01/02/2024] [Indexed: 02/07/2024] Open
Abstract
Moiré excitons (MXs) are electron-hole pairs localised by the periodic (moiré) potential forming in two-dimensional heterostructures (HSs). MXs can be exploited, e.g., for creating nanoscale-ordered quantum emitters and achieving or probing strongly correlated electronic phases at relatively high temperatures. Here, we studied the exciton properties of WSe2/MoSe2 HSs from T = 6 K to room temperature using time-resolved and continuous-wave micro-photoluminescence also under a magnetic field. The exciton dynamics and emission lineshape evolution with temperature show clear signatures that MXs de-trap from the moiré potential and turn into free interlayer excitons (IXs) for temperatures above 100 K. The MX-to-IX transition is also apparent from the exciton magnetic moment reversing its sign when the moiré potential is not capable of localising excitons at elevated temperatures. Concomitantly, the exciton formation and decay times reduce drastically. Thus, our findings establish the conditions for a truly confined nature of the exciton states in a moiré superlattice with increasing temperature and photo-generated carrier density.
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Affiliation(s)
- Elena Blundo
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Federico Tuzi
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Salvatore Cianci
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Marzia Cuccu
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Katarzyna Olkowska-Pucko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Łucja Kipczak
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Giorgio Contestabile
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Antonio Miriametro
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Marco Felici
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy
| | - Giorgio Pettinari
- Institute for Photonics and Nanotechnologies, National Research Council, 00133, Rome, Italy
| | - 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
| | - Adam Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Maciej R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Pasteura 5, 02-093, Warsaw, Poland
| | - Antonio Polimeni
- Physics Department, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185, Rome, Italy.
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6
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Qian C, Troue M, Figueiredo J, Soubelet P, Villafañe V, Beierlein J, Klembt S, Stier AV, Höfling S, Holleitner AW, Finley JJ. Lasing of moiré trapped MoSe 2/WSe 2 interlayer excitons coupled to a nanocavity. SCIENCE ADVANCES 2024; 10:eadk6359. [PMID: 38198542 PMCID: PMC10780878 DOI: 10.1126/sciadv.adk6359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 12/11/2023] [Indexed: 01/12/2024]
Abstract
We report lasing of moiré trapped interlayer excitons (IXs) by integrating a pristine hBN-encapsulated MoSe2/WSe2 heterobilayer into a high-Q (>104) nanophotonic cavity. We control the cavity-IX detuning using a magnetic field and measure their dipolar coupling strength to be 78 ± 4 micro-electron volts, fully consistent with the 82 micro-electron volts predicted by theory. The emission from the cavity mode shows clear threshold-like behavior as the transition is tuned into resonance with the cavity. We observe a superlinear power dependence accompanied by a narrowing of the linewidth as the distinct features of lasing. The onset and prominence of these threshold-like behaviors are pronounced at resonance while weak off-resonance. Our results show that a lasing transition can be induced in interacting moiré IXs with macroscopic coherence extending over the length scale of the cavity mode. Such systems raise interesting perspectives for low-power switching and synaptic nanophotonic devices using two-dimensional materials.
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Affiliation(s)
- Chenjiang Qian
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Mirco Troue
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Johannes Figueiredo
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Pedro Soubelet
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Viviana Villafañe
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Johannes Beierlein
- Julius-Maximilians-Universität Würzburg, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Lehrstuhl für Technische Physik, Am Hubland, 97074 Würzburg, Germany
| | - Sebastian Klembt
- Julius-Maximilians-Universität Würzburg, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Lehrstuhl für Technische Physik, Am Hubland, 97074 Würzburg, Germany
| | - Andreas V. Stier
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
| | - Sven Höfling
- Julius-Maximilians-Universität Würzburg, Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Lehrstuhl für Technische Physik, Am Hubland, 97074 Würzburg, Germany
| | - Alexander W. Holleitner
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Jonathan J. Finley
- Walter Schottky Institut and TUM School of Natural Science, Technische Universität München, Am Coulombwall 4, 85748 Garching, Germany
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7
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Bai Y, Li Y, Liu S, Guo Y, Pack J, Wang J, Dean CR, Hone J, Zhu X. Evidence for Exciton Crystals in a 2D Semiconductor Heterotrilayer. NANO LETTERS 2023; 23:11621-11629. [PMID: 38071655 DOI: 10.1021/acs.nanolett.3c03453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDC) and their moiré interfaces have been demonstrated for correlated electron states, including Mott insulators and electron/hole crystals commensurate with moiré superlattices. Here we present spectroscopic evidence for ordered bosons─interlayer exciton crystals in a WSe2/MoSe2/WSe2 trilayer, where the enhanced Coulomb interactions over those in heterobilayers have been predicted to result in exciton ordering. Ordered interlayer excitons in the trilayer are characterized by negligible mobility and by sharper PL peaks persisting to an exciton density of nex ∼ 1012 cm-2, which is an order of magnitude higher than the corresponding limit in the heterobilayer. We present evidence for the predicted quadrupolar exciton crystal and its transitions to dipolar excitons either with increasing nex or by an applied electric field. These ordered interlayer excitons may serve as models for the exploration of quantum phase transitions and quantum coherent phenomena.
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Affiliation(s)
- Yusong Bai
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Yiliu Li
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Song Liu
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Yinjie Guo
- Department of Physics and Astronomy, Columbia University, New York, New York 10027, United States
| | - Jordan Pack
- Department of Physics and Astronomy, Columbia University, New York, New York 10027, United States
| | - Jue Wang
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Cory R Dean
- Department of Physics and Astronomy, Columbia University, New York, New York 10027, United States
| | - James Hone
- Department of Mechanical Engineering, Columbia University, New York, New York 10027, United States
| | - Xiaoyang Zhu
- Department of Chemistry, Columbia University, New York, New York 10027, United States
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8
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Lei Y, Xie X, Ma H, Ma J. Vitality of Intralayer Vibration in hBN for Effective Long-Range Interlayer Hole Transfer across High Barriers in MoSe 2/hBN/WSe 2 Heterostructures. J Phys Chem Lett 2023:11190-11199. [PMID: 38055859 DOI: 10.1021/acs.jpclett.3c03040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/08/2023]
Abstract
Introducing the two-dimensional (2D) hexagonal boron nitride (hBN) between 2D transition metal dichalcogenide (TMD) layers promises convenient manipulation of the interlayer exciton (IX) and interlayer charge transfer in TMD/hBN/TMD heterostructures, while the role of inserted hBN layers during IX formation is controversial. Employing ab initio nonadiabatic molecular dynamics (NAMD) simulations and the electron-phonon coupling model, we systematically investigate interlayer hole transfer in MoSe2/WSe2 bilayers intercalated by hBN layers with various thicknesses. The conventional direct hole transfer from MoSe2 to WSe2 is decelerated by 2-3 orders of magnitude after the hBN insertion. Meanwhile, a novel channel intermediated by a deeper hole of WSe2 becomes dominant, where the intralayer shear mode of hBN plays a crucial role by reducing the energy barriers for this new channel. The unique role of hBN layers is revealed for the first time, enriching the knowledge of the underlying microscopic mechanisms and providing instructive guidance to practical van der Waals optoelectronic devices.
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Affiliation(s)
- Yuli Lei
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
| | - Xiaoyu Xie
- Qingdao Institute for Theoretical and Computational Sciences, Qingdao Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, China
| | - Haibo Ma
- Qingdao Institute for Theoretical and Computational Sciences, Qingdao Institute of Frontier and Interdisciplinary Science, Shandong University, Qingdao 266237, China
| | - Jing Ma
- Key Laboratory of Mesoscopic Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China
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9
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Fang H, Lin Q, Zhang Y, Thompson J, Xiao S, Sun Z, Malic E, Dash SP, Wieczorek W. Localization and interaction of interlayer excitons in MoSe 2/WSe 2 heterobilayers. Nat Commun 2023; 14:6910. [PMID: 37903787 PMCID: PMC10616232 DOI: 10.1038/s41467-023-42710-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/19/2023] [Indexed: 11/01/2023] Open
Abstract
Transition metal dichalcogenide (TMD) heterobilayers provide a versatile platform to explore unique excitonic physics via the properties of the constituent TMDs and external stimuli. Interlayer excitons (IXs) can form in TMD heterobilayers as delocalized or localized states. However, the localization of IX in different types of potential traps, the emergence of biexcitons in the high-excitation regime, and the impact of potential traps on biexciton formation have remained elusive. In our work, we observe two types of potential traps in a MoSe2/WSe2 heterobilayer, which result in significantly different emission behavior of IXs at different temperatures. We identify the origin of these traps as localized defect states and the moiré potential of the TMD heterobilayer. Furthermore, with strong excitation intensity, a superlinear emission behavior indicates the emergence of interlayer biexcitons, whose formation peaks at a specific temperature. Our work elucidates the different excitation and temperature regimes required for the formation of both localized and delocalized IX and biexcitons and, thus, contributes to a better understanding and application of the rich exciton physics in TMD heterostructures.
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Affiliation(s)
- Hanlin Fang
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden.
| | - Qiaoling Lin
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Yi Zhang
- Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto University, Espoo, 02150, Finland
| | - Joshua Thompson
- Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany
| | - Sanshui Xiao
- Department of Electrical and Photonics Engineering, Technical University of Denmark, DK-2800, Kongens Lyngby, Denmark
| | - Zhipei Sun
- Department of Electronics and Nanoengineering and QTF Centre of Excellence, Aalto University, Espoo, 02150, Finland
| | - Ermin Malic
- Department of Physics, Philipps-Universität Marburg, 35037, Marburg, Germany
| | - Saroj P Dash
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden
| | - Witlef Wieczorek
- Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, 41296, Gothenburg, Sweden.
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10
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Cai H, Rasmita A, Tan Q, Lai JM, He R, Cai X, Zhao Y, Chen D, Wang N, Mu Z, Huang Z, Zhang Z, Eng JJH, Liu Y, She Y, Pan N, Miao Y, Wang X, Liu X, Zhang J, Gao W. Interlayer donor-acceptor pair excitons in MoSe 2/WSe 2 moiré heterobilayer. Nat Commun 2023; 14:5766. [PMID: 37723156 PMCID: PMC10507070 DOI: 10.1038/s41467-023-41330-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 08/31/2023] [Indexed: 09/20/2023] Open
Abstract
Localized interlayer excitons (LIXs) in two-dimensional moiré superlattices exhibit sharp and dense emission peaks, making them promising as highly tunable single-photon sources. However, the fundamental nature of these LIXs is still elusive. Here, we show the donor-acceptor pair (DAP) mechanism as one of the origins of these excitonic peaks. Numerical simulation results of the DAP model agree with the experimental photoluminescence spectra of LIX in the moiré MoSe2/WSe2 heterobilayer. In particular, we find that the emission energy-lifetime correlation and the nonmonotonic power dependence of the lifetime agree well with the DAP IX model. Our results provide insight into the physical mechanism of LIX formation in moiré heterostructures and pave new directions for engineering interlayer exciton properties in moiré superlattices.
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Affiliation(s)
- Hongbing Cai
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, 637371, Singapore
| | - Abdullah Rasmita
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Qinghai Tan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Jia-Min Lai
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China
- Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ruihua He
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Xiangbin Cai
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yan Zhao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Disheng Chen
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, 637371, Singapore
| | - Naizhou Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Zhao Mu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Zumeng Huang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - Zhaowei Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
| | - John J H Eng
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- Institute of Materials Research and Engineering, Agency for Science, Technology and Research, Singapore, Singapore
| | - Yuanda Liu
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, 637371, Singapore
| | - Yongzhi She
- Department of Physics, University of Science and Technology of China, Hefei Anhui, 230026, China
| | - Nan Pan
- Department of Physics, University of Science and Technology of China, Hefei Anhui, 230026, China
| | - Yansong Miao
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551, Singapore
| | - Xiaoping Wang
- Department of Physics, University of Science and Technology of China, Hefei Anhui, 230026, China
| | - Xiaogang Liu
- Department of Chemistry, National University of Singapore, Singapore, 117543, Singapore
| | - Jun Zhang
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, China.
| | - Weibo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore, 637371, Singapore.
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore, 637371, Singapore.
- Centre for Quantum Technologies, National University of Singapore, Singapore, Singapore.
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11
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Ge C, Zhang D, Xiao F, Zhao H, He M, Huang L, Hou S, Tong Q, Pan A, Wang X. Observation and Modulation of High-Temperature Moiré-Locale Excitons in van der Waals Heterobilayers. ACS NANO 2023; 17:16115-16122. [PMID: 37560986 DOI: 10.1021/acsnano.3c04943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
Transition metal dichalcogenide heterobilayers feature strong moiré potentials with multiple local minima, which can spatially trap interlayer excitons at different locations within one moiré unit cell (dubbed moiré locales). However, current studies mainly focus on moiré excitons trapped at a single moiré locale. Exploring interlayer excitons trapped at different moiré locales is highly desirable for building polarized light-emitter arrays and studying multiorbital correlated and topological physics. Here, via enhancing the interlayer coupling and engineering the heterointerface, we report the observation and modulation of high-temperature interlayer excitons trapped at separate moiré locales in WS2/WSe2 heterobilayers. These moiré-locale excitons are identified by two emission peaks with an energy separation of ∼60 meV, exhibiting opposite circular polarizations due to their distinct local stacking registries. With the increase of temperature, two momentum-indirect moiré-locale excitons are observed, which show a distinct strain dependence with the momentum-direct one. The emission of these moiré-locale excitons can be controlled via engineering the heterointerface with different phonon scattering, while their emission energy can be further modulated via strain engineering. Our reported highly tunable interlayer excitons provide important information on understanding moiré excitonic physics, with possible applications in building high-temperature excitonic devices.
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Affiliation(s)
- Cuihuan Ge
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Danliang Zhang
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Feiping Xiao
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Haipeng Zhao
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Mai He
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Lanyu Huang
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Shijin Hou
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Qingjun Tong
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
| | - Xiao Wang
- School of Physics and Electronics, Hunan University, Changsha, 410082, China
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha, 410082, China
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12
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Montblanch ARP, Barbone M, Aharonovich I, Atatüre M, Ferrari AC. Layered materials as a platform for quantum technologies. NATURE NANOTECHNOLOGY 2023:10.1038/s41565-023-01354-x. [PMID: 37322143 DOI: 10.1038/s41565-023-01354-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 02/17/2023] [Indexed: 06/17/2023]
Abstract
Layered materials are taking centre stage in the ever-increasing research effort to develop material platforms for quantum technologies. We are at the dawn of the era of layered quantum materials. Their optical, electronic, magnetic, thermal and mechanical properties make them attractive for most aspects of this global pursuit. Layered materials have already shown potential as scalable components, including quantum light sources, photon detectors and nanoscale sensors, and have enabled research of new phases of matter within the broader field of quantum simulations. In this Review we discuss opportunities and challenges faced by layered materials within the landscape of material platforms for quantum technologies. In particular, we focus on applications that rely on light-matter interfaces.
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Affiliation(s)
- Alejandro R-P Montblanch
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, Delft, The Netherlands
| | - Matteo Barbone
- Cavendish Laboratory, University of Cambridge, Cambridge, UK
- Cambridge Graphene Centre, University of Cambridge, Cambridge, UK
- Munich Center for Quantum Science and Technology, (MCQST), Munich, Germany
- Walter Schottky Institut and Department of Electrical and Computer Engineering, Technische Universität München, Garching, Germany
| | - Igor Aharonovich
- School of Mathematical and Physical Sciences, University of Technology Sydney, Ultimo, New South Wales, Sydney, Australia
- Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, University of Technology Sydney, Ultimo, New South Wales, Sydney, Australia
| | - Mete Atatüre
- Cavendish Laboratory, University of Cambridge, Cambridge, UK.
| | - Andrea C Ferrari
- Cambridge Graphene Centre, University of Cambridge, Cambridge, UK.
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13
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Zheng H, Wu B, Li S, He J, Liu Z, Wang CT, Wang JT, Duan JA, Liu Y. Strain-tunable valley polarization and localized excitons in monolayer WSe 2. OPTICS LETTERS 2023; 48:2393-2396. [PMID: 37126281 DOI: 10.1364/ol.487201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Monolayer transition metal dichalcogenides (TMDs) have a crystalline structure with broken spatial inversion symmetry, making them promising candidates for valleytronic applications. However, the degree of valley polarization is usually not high due to the presence of intervalley scattering. Here, we use the nanoindentation technique to fabricate strained structures of WSe2 on Au arrays, thus demonstrating the generation and detection of strained localized excitons in monolayer WSe2. Enhanced emission of strain-localized excitons was observed as two sharp photoluminescence (PL) peaks measured using low-temperature PL spectroscopy. We attribute these emerging sharp peaks to excitons trapped in potential wells formed by local strains. Furthermore, the valley polarization of monolayer WSe2 is modulated by a magnetic field, and the valley polarization of strained localized excitons is increased, with a high value of up to approximately 79.6%. Our results show that tunable valley polarization and localized excitons can be realized in WSe2 monolayers, which may be useful for valleytronic applications.
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14
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Tan Q, Rasmita A, Zhang Z, Novoselov KS, Gao WB. Signature of Cascade Transitions between Interlayer Excitons in a Moiré Superlattice. PHYSICAL REVIEW LETTERS 2022; 129:247401. [PMID: 36563256 DOI: 10.1103/physrevlett.129.247401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
A moiré superlattice in transition metal dichalcogenides heterostructure provides an exciting platform for studying strongly correlated electronics and excitonic physics, such as multiple interlayer exciton (IX) energy bands. However, the correlations between these IXs remain elusive. Here, we demonstrate the cascade transitions between IXs in a moiré superlattice by performing energy- and time-resolved photoluminescence measurements in the MoS_{2}/WSe_{2} heterostructure. Furthermore, we show that the lower-energy IX can be excited to higher-energy ones, facilitating IX population inversion. Our finding of cascade transitions between IXs contributes to the fundamental understanding of the IX dynamics in moiré superlattices and may have important applications, such as in exciton condensate, quantum information protocols, and quantum cascade lasers.
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Affiliation(s)
- Qinghai Tan
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
| | - Abdullah Rasmita
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - Zhaowei Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
| | - K S Novoselov
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore
| | - Wei-Bo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371, Singapore
- Centre for Quantum Technologies, National University of Singapore, 117543 Singapore, Singapore
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15
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Li K, Xiao F, Guan W, Xiao Y, Xu C, Zhang J, Lin C, Li D, Tong Q, Li SY, Pan A. Morphology Deformation and Giant Electronic Band Modulation in Long-Wavelength WS 2 Moiré Superlattices. NANO LETTERS 2022; 22:5997-6003. [PMID: 35839083 DOI: 10.1021/acs.nanolett.2c02418] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
As a lattice interference effect, moiré superlattices feature a magnification effect that they respond sensitively to both the extrinsic mechanical perturbations and intrinsic atomic reconstructions. Here, using scanning tunneling microscopy and spectroscopy, we observe that long-wavelength WS2 superlattices are reconstructed into various moiré morphologies, ranging from regular hexagons to heavily deformed ones. We show that a dedicated interplay between the extrinsic nonuniform heterostrain and the intrinsic atomic reconstruction is responsible for this interesting moiré structure evolution. Importantly, the interplay between these two factors also introduces a local inhomogeneous intralayer strain within a moiré. Contrary to the commonly reported electronic modulation that occurred at the valence band edge due to interlayer hybridization, we find that this local intralayer strain induces a strong modulation at K point of the conduction band, reaching up to 300 meV in the heavily deformed moiré. Our microscopic explorations provide valuable information in understanding the intriguing physics in TMD moirés.
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Affiliation(s)
- Kaihui Li
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Feiping Xiao
- School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Wen Guan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Yulong Xiao
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Chang Xu
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Jinding Zhang
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Chenfang Lin
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Dong Li
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Qingjun Tong
- School of Physics and Electronics, Hunan University, Changsha 410082, People's Republic of China
| | - Si-Yu Li
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, College of Materials Science and Engineering, Hunan University, Changsha 410082, People's Republic of China
- Hunan Institute of Optoelectronic Integration, Hunan University, Changsha 410082, People's Republic of China
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