1
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Wang N, You JY, Wang A, Zhou X, Zhang Z, Lai S, Feng YP, Lin H, Chang G, Gao WB. Non-centrosymmetric topological phase probed by non-linear Hall effect. Natl Sci Rev 2024; 11:nwad103. [PMID: 38725935 PMCID: PMC11081079 DOI: 10.1093/nsr/nwad103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/22/2022] [Accepted: 02/09/2023] [Indexed: 05/12/2024] Open
Abstract
Non-centrosymmetric topological material has attracted intense attention due to its superior characteristics as compared with the centrosymmetric one, although probing the local quantum geometry in non-centrosymmetric topological material remains challenging. The non-linear Hall (NLH) effect provides an ideal tool to investigate the local quantum geometry. Here, we report a non-centrosymmetric topological phase in ZrTe5, probed by using the NLH effect. The angle-resolved and temperature-dependent NLH measurement reveals the inversion and ab-plane mirror symmetries breaking at <30 K, consistently with our theoretical calculation. Our findings identify a new non-centrosymmetric phase of ZrTe5 and provide a platform to probe and control local quantum geometry via crystal symmetries.
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Affiliation(s)
- Naizhou Wang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Jing-Yang You
- Department of Physics, National University of Singapore, Singapore 117551
| | - Aifeng Wang
- Low Temperature Physics Laboratory, College of Physics and Center for Quantum Materials and Devices, Chongqing University, Chongqing 401331
| | - Xiaoyuan Zhou
- Low Temperature Physics Laboratory, College of Physics and Center for Quantum Materials and Devices, Chongqing University, Chongqing 401331
| | - Zhaowei Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Shen Lai
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Yuan-Ping Feng
- Department of Physics, National University of Singapore, Singapore 117551
- Centre for Advanced 2D Materials, National University of Singapore, Singapore 117546
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei 11529
| | - Guoqing Chang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
| | - Wei-bo Gao
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371
- The Photonics Institute and Centre for Disruptive Photonic Technologies, Nanyang Technological University, Singapore 637371
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2
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Wang X, Tian H, Li X, Wang F, Zhai L, Zhu X, Liu JM, Yang Y. Pressure-Induced Topological Phase Transition and Large Rashba Effect in Halide Double Perovskite. J Phys Chem Lett 2024; 15:1477-1483. [PMID: 38295292 DOI: 10.1021/acs.jpclett.3c03432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
In general, hydrostatic pressure can suppress ferroelectric polarization and further reduce Rashba spin-splitting, considering the spin-orbit coupling effect. Here, we present the design of ferroelectric double perovskite Cs2SnSiI6, which exhibits the anomalous enhancement of Rashba spin-splitting parameters by pressure-induced ferroelectric topological order. The Rashba effect is nonlinear with the decrease in polarization under pressure and reaches a maximum at the pressure-induced Weyl semimetal (WSM) state between the transition from a normal insulator (NI) to a topological insulator (TI). Furthermore, we discover that controlling ferroelectric polarization with an electric field can also induce the topological transition with a large Rashba spin-splitting but under a lower critical pressure. These discoveries show a tunable gaint Rashba effect and pressure-induced topological phase transition for Cs2SnSiI6, which can promote future research on the interaction between the Rashba effect and topological order, and its application to new electronic and spintronic devices.
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Affiliation(s)
- Xinyu Wang
- The School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China
| | - Hao Tian
- School of Physics and Electronic Engineering, Zhengzhou Normal University, Zhengzhou 450044, China
| | - Xu Li
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
- Jiangsu Key Laboratory of Artificial Functional Materials, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China
| | - Fengfei Wang
- The School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China
| | - Liangjun Zhai
- The School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China
| | - Xiaoqin Zhu
- The School of Mathematics and Physics, Jiangsu University of Technology, Changzhou 213001, China
| | - Jun-Ming Liu
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
| | - Yurong Yang
- Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China
- Jiangsu Key Laboratory of Artificial Functional Materials, Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China
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3
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Qiu G, Yang HY, Chong SK, Cheng Y, Tai L, Wang KL. Manipulating Topological Phases in Magnetic Topological Insulators. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2655. [PMID: 37836296 PMCID: PMC10574534 DOI: 10.3390/nano13192655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023]
Abstract
Magnetic topological insulators (MTIs) are a group of materials that feature topological band structures with concurrent magnetism, which can offer new opportunities for technological advancements in various applications, such as spintronics and quantum computing. The combination of topology and magnetism introduces a rich spectrum of topological phases in MTIs, which can be controllably manipulated by tuning material parameters such as doping profiles, interfacial proximity effect, or external conditions such as pressure and electric field. In this paper, we first review the mainstream MTI material platforms where the quantum anomalous Hall effect can be achieved, along with other exotic topological phases in MTIs. We then focus on highlighting recent developments in modulating topological properties in MTI with finite-size limit, pressure, electric field, and magnetic proximity effect. The manipulation of topological phases in MTIs provides an exciting avenue for advancing both fundamental research and practical applications. As this field continues to develop, further investigations into the interplay between topology and magnetism in MTIs will undoubtedly pave the way for innovative breakthroughs in the fundamental understanding of topological physics as well as practical applications.
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Affiliation(s)
- Gang Qiu
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA 90095, USA; (H.-Y.Y.); (S.K.C.); (Y.C.); (L.T.)
- Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Hung-Yu Yang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA 90095, USA; (H.-Y.Y.); (S.K.C.); (Y.C.); (L.T.)
| | - Su Kong Chong
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA 90095, USA; (H.-Y.Y.); (S.K.C.); (Y.C.); (L.T.)
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Yang Cheng
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA 90095, USA; (H.-Y.Y.); (S.K.C.); (Y.C.); (L.T.)
| | - Lixuan Tai
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA 90095, USA; (H.-Y.Y.); (S.K.C.); (Y.C.); (L.T.)
| | - Kang L. Wang
- Department of Electrical and Computer Engineering, University of California, Los Angeles, CA 90095, USA; (H.-Y.Y.); (S.K.C.); (Y.C.); (L.T.)
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4
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Cai L, Yu C, Zhao W, Li Y, Feng H, Zhou HA, Wang L, Zhang X, Zhang Y, Shi Y, Zhang J, Yang L, Jiang W. The Giant Spin-to-Charge Conversion of the Layered Rashba Material BiTeI. NANO LETTERS 2022; 22:7441-7448. [PMID: 36099337 DOI: 10.1021/acs.nanolett.2c02354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Rashba spin-orbit coupling (SOC) could facilitate an efficient interconversion between spin and charge currents. Among various systems, BiTeI holds one of the largest Rashba-type spin splittings. Unlike other Rashba systems (e.g., Bi/Ag and Bi2Se3), an experimental investigation of the spin-to-charge interconversion in BiTeI remains to be explored. Through performing an angle-resolved photoemission spectroscopy (ARPES) measurement, such a large Rashba-type spin splitting with a Rashba parameter αR = 3.68 eV Å is directly identified. By studying the spin pumping effect in the BiTeI/NiFe bilayer, we reveal a very large inverse Rashba-Edelstein length λIREE ≈ 1.92 nm of BiTeI at room temperature. Furthermore, the λIREE monotonously increases to 5.00 nm at 60 K, indicating an enhanced Rashba SOC at low temperature. These results suggest that BiTeI films with the giant Rashba SOC are promising for achieving efficient spin-to-charge interconversion, which could be implemented for building low-power-consumption spin-orbitronic devices.
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Affiliation(s)
- Li Cai
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Chenglin Yu
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Wenxuan Zhao
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Yong Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Hongmei Feng
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Heng-An Zhou
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Ledong Wang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Xiaofang Zhang
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Ying Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Youguo Shi
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jinsong Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Lexian Yang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
| | - Wanjun Jiang
- State Key Laboratory of Low-Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing 100084, China
- Frontier Science Center for Quantum Information, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100084, China
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5
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Rajaji V, Manjón FJ, Narayana C. Pressure induced topological and topological crystalline insulators. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:423001. [PMID: 35952626 DOI: 10.1088/1361-648x/ac8906] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/11/2022] [Indexed: 06/15/2023]
Abstract
Research on topological and topological crystalline insulators (TCIs) is one of the most intense and exciting topics due to its fascinating fundamental science and potential technological applications. Pressure (strain) is one potential pathway to induce the non-trivial topological phases in some topologically trivial (normal) insulating or semiconducting materials. In the last ten years, there have been substantial theoretical and experimental efforts from condensed-matter scientists to characterize and understand pressure-induced topological quantum phase transitions (TQPTs). In particular, a promising enhancement of the thermoelectric performance through pressure-induced TQPT has been recently realized; thus evidencing the importance of this subject in society. Since the pressure effect can be mimicked by chemical doping or substitution in many cases, these results have opened a new route to develop more efficient materials for harvesting green energy at ambient conditions. Therefore, a detailed understanding of the mechanism of pressure-induced TQPTs in various classes of materials with spin-orbit interaction is crucial to improve their properties for technological implementations. Hence, this review focuses on the emerging area of pressure-induced TQPTs to provide a comprehensive understanding of this subject from both theoretical and experimental points of view. In particular, it covers the Raman signatures of detecting the topological transitions (under pressure), some of the important pressure-induced topological and TCIs of the various classes of spin-orbit coupling materials, and provide future research directions in this interesting field.
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Affiliation(s)
- V Rajaji
- University Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
- School of Advance Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
| | - F J Manjón
- Instituto de Diseño para la Fabricación y Producción Automatizada, MALTA Consolider Team, Universitat Politècnica de València, 46022 Valencia, Spain
| | - Chandrabhas Narayana
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
- School of Advance Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India
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6
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Bianca G, Trovatello C, Zilli A, Zappia MI, Bellani S, Curreli N, Conticello I, Buha J, Piccinni M, Ghini M, Celebrano M, Finazzi M, Kriegel I, Antonatos N, Sofer Z, Bonaccorso F. Liquid-Phase Exfoliation of Bismuth Telluride Iodide (BiTeI): Structural and Optical Properties of Single-/Few-Layer Flakes. ACS APPLIED MATERIALS & INTERFACES 2022; 14:34963-34974. [PMID: 35876692 PMCID: PMC9354013 DOI: 10.1021/acsami.2c07704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Bismuth telluride halides (BiTeX) are Rashba-type crystals with several potential applications ranging from spintronics and nonlinear optics to energy. Their layered structures and low cleavage energies allow their production in a two-dimensional form, opening the path to miniaturized device concepts. The possibility to exfoliate bulk BiTeX crystals in the liquid represents a useful tool to formulate a large variety of functional inks for large-scale and cost-effective device manufacturing. Nevertheless, the exfoliation of BiTeI by means of mechanical and electrochemical exfoliation proved to be challenging. In this work, we report the first ultrasonication-assisted liquid-phase exfoliation (LPE) of BiTeI crystals. By screening solvents with different surface tension and Hildebrandt parameters, we maximize the exfoliation efficiency by minimizing the Gibbs free energy of the mixture solvent/BiTeI crystal. The most effective solvents for the BiTeI exfoliation have a surface tension close to 28 mN m-1 and a Hildebrandt parameter between 19 and 25 MPa0.5. The morphological, structural, and chemical properties of the LPE-produced single-/few-layer BiTeI flakes (average thickness of ∼3 nm) are evaluated through microscopic and optical characterizations, confirming their crystallinity. Second-harmonic generation measurements confirm the non-centrosymmetric structure of both bulk and exfoliated materials, revealing a large nonlinear optical response of BiTeI flakes due to the presence of strong quantum confinement effects and the absence of typical phase-matching requirements encountered in bulk nonlinear crystals. We estimated a second-order nonlinearity at 0.8 eV of |χ(2)| ∼ 1 nm V-1, which is 10 times larger than in bulk BiTeI crystals and is of the same order of magnitude as in other semiconducting monolayers (e.g., MoS2).
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Affiliation(s)
- Gabriele Bianca
- Graphene
Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università
degli Studi di Genova, via Dodecaneso 31, 16146 Genoa, Italy
| | - Chiara Trovatello
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Attilio Zilli
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marilena Isabella Zappia
- BeDimensional
S.p.A., via Lungotorrente
Secca 30R, 16163 Genova, Italy
- Department
of Physics, University of Calabria, Via P. Bucci cubo 31/C Rende, Cosenza 87036, Italy
| | | | - Nicola Curreli
- Functional
Nanosystems, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
| | - Irene Conticello
- BeDimensional
S.p.A., via Lungotorrente
Secca 30R, 16163 Genova, Italy
| | - Joka Buha
- Nanochemistry
Department, Istituto Italiano di Tecnologia, via Morego 30, Genova 16163, Italy
| | - Marco Piccinni
- Graphene
Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- Dipartimento
di Chimica e Chimica Industriale, Università
degli Studi di Genova, via Dodecaneso 31, 16146 Genoa, Italy
| | - Michele Ghini
- Functional
Nanosystems, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
| | - Michele Celebrano
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marco Finazzi
- Dipartimento
di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Ilka Kriegel
- Functional
Nanosystems, Istituto Italiano di Tecnologia, via Morego, 30, 16163 Genova, Italy
| | - Nikolas Antonatos
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Zdeněk Sofer
- Department
of Inorganic Chemistry, University of Chemistry
and Technology Prague, Technická 5, 16628 Prague 6, Czech Republic
| | - Francesco Bonaccorso
- Graphene
Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
- BeDimensional
S.p.A., via Lungotorrente
Secca 30R, 16163 Genova, Italy
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7
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Zhao Z, Wang H, Tan H, Wu X, Kang Y, Dong Y, Li X, Jin S, Chang X. Deciphering the active origin for urea oxidation reaction over nitrogen penetrated nickel nanoparticles embedded in carbon nanotubes. J Colloid Interface Sci 2022; 626:740-751. [DOI: 10.1016/j.jcis.2022.06.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/26/2022] [Accepted: 06/24/2022] [Indexed: 10/31/2022]
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8
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Evidence of magnetism-induced topological protection in the axion insulator candidate EuSn 2P 2. Proc Natl Acad Sci U S A 2022; 119:2116575119. [PMID: 35042814 PMCID: PMC8795521 DOI: 10.1073/pnas.2116575119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2021] [Indexed: 11/18/2022] Open
Abstract
We unravel the interplay of topological properties and the layered (anti)ferromagnetic ordering in EuSn2P2, using spin and chemical selective electron and X-ray spectroscopies supported by first-principle calculations. We reveal the presence of in-plane long-range ferromagnetic order triggering topological invariants and resulting in the multiple protection of topological Dirac states. We provide clear evidence that layer-dependent spin-momentum locking coexists with ferromagnetism in this material, a cohabitation that promotes EuSn2P2 as a prime candidate axion insulator for topological antiferromagnetic spintronics applications.
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9
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Wu YL, Yin X, Hasaien JZL, Tian ZY, Ding Y, Zhao J. On-site in situ high-pressure ultrafast pump-probe spectroscopy instrument. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:113002. [PMID: 34852544 DOI: 10.1063/5.0064071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/09/2021] [Indexed: 06/13/2023]
Abstract
We conceive and construct an on-site in situ high-pressure time-resolved ultrafast optical spectroscopy instrument that facilitates ultrafast pump-probe dynamics measurements under high pressure conditions. We integrate an ultrafast pump-probe spectroscopy system with a diamond anvil cell (DAC) system. Significantly, both the DAC and the sample are fixed within the light path without motion and rotation throughout the whole ultrafast spectroscopy experiment, including tuning and calibrating the pressure. This instrument thus avoids introducing artifacts due to sample motion or rotation, enabling precision high-pressure ultrafast pump-probe dynamics investigations. As a demonstrating example, we compare the effect of on-site in situ conditions with off-site in situ conditions on the ultrafast dynamics of Sr2IrO4 under 0-44.5 GPa high pressure. Our data and analysis show that conventional possible artifacts are greatly reduced by using the on-site in situ layout. Our work helps the high-pressure ultrafast science investigation develop into a promising new area, which enables the exploration of nonequilibrium excited quantum states in the high-pressure regime.
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Affiliation(s)
- Y L Wu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - X Yin
- Center for High-Pressure Sciences and Technology Advanced Research, Beijing 100094, China
| | - J Z L Hasaien
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Z Y Tian
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yang Ding
- Center for High-Pressure Sciences and Technology Advanced Research, Beijing 100094, China
| | - Jimin Zhao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
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10
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Bose A, Narayan A. Strain-induced topological charge control in multifold fermion systems. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:375002. [PMID: 34186528 DOI: 10.1088/1361-648x/ac0fa0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 06/29/2021] [Indexed: 06/13/2023]
Abstract
Multifold fermion systems feature free fermionic excitations, which have no counterparts in high-energy physics, and exhibit several unconventional properties. Using first-principles calculations, we predict that strain engineering can be used to control the distribution of topological charges in transition metal silicide candidate CoSi, hosting multifold fermions. We demonstrate that breaking the rotational symmetry of the system, by choosing a suitable strain, destroys the multifold fermions, and at the same time results in the creation of Weyl points. We introduce a low energy effective model to complement the results obtained from density functional calculations. Our findings suggest that strain-engineering is a useful approach to tune topological properties of multifold fermions.
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Affiliation(s)
- Anumita Bose
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
| | - Awadhesh Narayan
- Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
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11
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Yamamoto D, Sakurai T, Okuto R, Okubo S, Ohta H, Tanaka H, Uwatoko Y. Continuous control of classical-quantum crossover by external high pressure in the coupled chain compound CsCuCl 3. Nat Commun 2021; 12:4263. [PMID: 34253735 PMCID: PMC8275658 DOI: 10.1038/s41467-021-24542-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/23/2021] [Indexed: 11/16/2022] Open
Abstract
In solid materials, the parameters relevant to quantum effects, such as the spin quantum number, are basically determined and fixed at the chemical synthesis, which makes it challenging to control the amount of quantum correlations. We propose and demonstrate a method for active control of the classical-quantum crossover in magnetic insulators by applying external pressure. As a concrete example, we perform high-field, high-pressure measurements on CsCuCl3, which has the structure of weakly-coupled spin chains. The magnetization process experiences a continuous evolution from the semi-classical realm to the highly-quantum regime with increasing pressure. Based on the idea of "squashing” the spin chains onto a plane, we characterize the change in the quantum correlations by the change in the value of the local spin quantum number of an effective two-dimensional model. This opens a way to access the tunable classical-quantum crossover of two-dimensional spin systems by using alternative systems of coupled-chain compounds. In real materials, a spin quantum number assumes a fixed value, which makes it challenging to realize a crossover between quantum and classical spin regimes. Here the authors demonstrate such a crossover in a weakly coupled chain compound by controlling the amount of quantum correlations, in the form of the inverse spin quantum number, with external pressure.
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Affiliation(s)
- Daisuke Yamamoto
- Department of Physics, Nihon University, Tokyo, Japan. .,Department of Physics and Mathematics, Aoyama Gakuin University, Kanagawa, Japan.
| | - Takahiro Sakurai
- Research Facility Center for Science and Technology, Kobe University, Kobe, Japan.
| | - Ryosuke Okuto
- Graduate School of Science, Kobe University, Kobe, Japan
| | - Susumu Okubo
- Molecular Photoscience Research Center, Kobe University, Kobe, Japan
| | - Hitoshi Ohta
- Molecular Photoscience Research Center, Kobe University, Kobe, Japan
| | - Hidekazu Tanaka
- Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
| | - Yoshiya Uwatoko
- Institute for Solid State Physics, The University of Tokyo, Chiba, Japan
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12
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Xie YM, Gao XJ, Xu XY, Zhang CP, Hu JX, Gao JZ, Law KT. Kramers nodal line metals. Nat Commun 2021; 12:3064. [PMID: 34031382 PMCID: PMC8144424 DOI: 10.1038/s41467-021-22903-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 04/06/2021] [Indexed: 11/09/2022] Open
Abstract
Recently, it was pointed out that all chiral crystals with spin-orbit coupling (SOC) can be Kramers Weyl semimetals (KWSs) which possess Weyl points pinned at time-reversal invariant momenta. In this work, we show that all achiral non-centrosymmetric materials with SOC can be a new class of topological materials, which we term Kramers nodal line metals (KNLMs). In KNLMs, there are doubly degenerate lines, which we call Kramers nodal lines (KNLs), connecting time-reversal invariant momenta. The KNLs create two types of Fermi surfaces, namely, the spindle torus type and the octdong type. Interestingly, all the electrons on octdong Fermi surfaces are described by two-dimensional massless Dirac Hamiltonians. These materials support quantized optical conductance in thin films. We further show that KNLMs can be regarded as parent states of KWSs. Therefore, we conclude that all non-centrosymmetric metals with SOC are topological, as they can be either KWSs or KNLMs.
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Affiliation(s)
- Ying-Ming Xie
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xue-Jian Gao
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Xiao Yan Xu
- Department of Physics, University of California at San Diego, La Jolla, CA, USA
| | - Cheng-Ping Zhang
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Jin-Xin Hu
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - Jason Z Gao
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China
| | - K T Law
- Department of Physics, Hong Kong University of Science and Technology, Hong Kong, China.
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13
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Wang JR, Li W, Wang G, Zhang CJ. Global phase diagram of Coulomb-interacting anisotropic Weyl semimetal with disorder. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:125601. [PMID: 33326939 DOI: 10.1088/1361-648x/abd426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/16/2020] [Indexed: 06/12/2023]
Abstract
Taking into account the interplay between the disorder and Coulomb interaction, the phase diagram of three-dimensional anisotropic Weyl semimetal is studied by renormalization group (RG) theory. Weak disorder is irrelevant in anisotropic Weyl semimetal, while the disorder becomes relevant and drives a quantum phase transition (QPT) from semimetal to compressible diffusive metal (CDM) phases if the disorder strength is larger than a critical value. The long-range Coulomb interaction is irrelevant in clean anisotropic Weyl semimetal. However, interestingly, we find that the long-range Coulomb interaction exerts a dramatic influence on the critical disorder strength for phase transition to CDM. Specifically, the critical disorder strength can receive a prominent change even though an arbitrarily weak Coulomb interaction is included. This novel behavior is closely related to the anisotropic screening effect of Coulomb interaction, and essentially results from the specifical energy dispersion of the fermion excitations in anisotropic Weyl semimetal. The theoretical results are helpful for understanding the physical properties of the candidates of anisotropic Weyl semimetal, such as pressured BiTeI, and some other related materials.
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Affiliation(s)
- Jing-Rong Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Anhui Province, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Wei Li
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Gang Wang
- College of Physics, Optoelectronics and Energy, Soochow University, Suzhou 215006, People's Republic of China
| | - Chang-Jin Zhang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of Anhui Province, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- Institute of Physical Science and Information Technology, Anhui University, Hefei 230601, People's Republic of China
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14
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Kovács-Krausz Z, Hoque AM, Makk P, Szentpéteri B, Kocsis M, Fülöp B, Yakushev MV, Kuznetsova TV, Tereshchenko OE, Kokh KA, Lukács I, Taniguchi T, Watanabe K, Dash SP, Csonka S. Electrically Controlled Spin Injection from Giant Rashba Spin-Orbit Conductor BiTeBr. NANO LETTERS 2020; 20:4782-4791. [PMID: 32511931 PMCID: PMC7660945 DOI: 10.1021/acs.nanolett.0c00458] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 06/05/2020] [Indexed: 05/31/2023]
Abstract
Ferromagnetic materials are the widely used source of spin-polarized electrons in spintronic devices, which are controlled by external magnetic fields or spin-transfer torque methods. However, with increasing demand for smaller and faster spintronic components utilization of spin-orbit phenomena provides promising alternatives. New materials with unique spin textures are highly desirable since all-electric creation and control of spin polarization is expected where the strength, as well as an arbitrary orientation of the polarization, can be defined without the use of a magnetic field. In this work, we use a novel spin-orbit crystal BiTeBr for this purpose. Because of its giant Rashba spin splitting, bulk spin polarization is created at room temperature by an electric current. Integrating BiTeBr crystal into graphene-based spin valve devices, we demonstrate for the first time that it acts as a current-controlled spin injector, opening new avenues for future spintronic applications in integrated circuits.
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Affiliation(s)
- Zoltán Kovács-Krausz
- Department
of Physics, Budapest University of Technology
and Economics and Nanoelectronics ‘Momentum’ Research
Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
| | - Anamul Md Hoque
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, SE-41296, Göteborg, Sweden
| | - Péter Makk
- Department
of Physics, Budapest University of Technology
and Economics and Nanoelectronics ‘Momentum’ Research
Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
| | - Bálint Szentpéteri
- Department
of Physics, Budapest University of Technology
and Economics and Nanoelectronics ‘Momentum’ Research
Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
| | - Mátyás Kocsis
- Department
of Physics, Budapest University of Technology
and Economics and Nanoelectronics ‘Momentum’ Research
Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
| | - Bálint Fülöp
- Department
of Physics, Budapest University of Technology
and Economics and Nanoelectronics ‘Momentum’ Research
Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
| | - Michael Vasilievich Yakushev
- M.N.
Miheev Institute of Metal Physics, Ural
Branch of the Russian Academy of Science, 620108, Ekaterinburg, Russia
- Ural
Federal University, Ekaterinburg, 620002, Russia
- Institute
of Solid State Chemistry, Ural Branch of
the Russian Academy of Science, Ekaterinburg, 620990, Russia
| | - Tatyana Vladimirovna Kuznetsova
- M.N.
Miheev Institute of Metal Physics, Ural
Branch of the Russian Academy of Science, 620108, Ekaterinburg, Russia
- Ural
Federal University, Ekaterinburg, 620002, Russia
| | - Oleg Evgenevich Tereshchenko
- St.
Petersburg State University, 198504, St. Petersburg, Russia
- A.
V. Rzhanov Institute of Semiconductor Physics, 630090, Novosibirsk, Russia
- Novosibirsk
State University, 630090, Novosibirsk, Russia
| | - Konstantin Aleksandrovich Kokh
- St.
Petersburg State University, 198504, St. Petersburg, Russia
- Novosibirsk
State University, 630090, Novosibirsk, Russia
- V.
S. Sobolev Institute of Geology and Mineralogy, 630090, Novosibirsk, Russia
| | - István
Endre Lukács
- Center
for Energy Research, Institute of Technical
Physics and Material Science, H-1121 Budapest, Hungary
| | - Takashi Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Saroj Prasad Dash
- Department
of Microtechnology and Nanoscience, Chalmers
University of Technology, SE-41296, Göteborg, Sweden
| | - Szabolcs Csonka
- Department
of Physics, Budapest University of Technology
and Economics and Nanoelectronics ‘Momentum’ Research
Group of the Hungarian Academy of Sciences, Budafoki ut 8, 1111 Budapest, Hungary
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15
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Isaeva A, Ruck M. Crystal Chemistry and Bonding Patterns of Bismuth-Based Topological Insulators. Inorg Chem 2020; 59:3437-3451. [PMID: 32101423 DOI: 10.1021/acs.inorgchem.9b03461] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Bismuth is gaining importance as a key element of functional quantum materials. The effects of spin-orbit coupling (SOC) are at the heart of many exciting proposals for next-generation quantum technologies, including topological materials for efficient information transmission and energy-saving applications. The "heavy" element bismuth and its compounds are predestined for SOC-induced topological properties, but materials design is challenged by a complex link between them and the chemical composition and crystal structure. Nevertheless, a lot can be learned about a certain property by testing its limits with compositional and/or structure modifications. We survey a handful of topological bismuth-based materials that bear structural and chemical semblance to the early topological insulators, antimony-doped elemental bismuth, Bi2Se3 and Bi2Te3. Chemical bonding via p orbitals and modular structure underlie all considered bismuth chalcogenides, subhalides, and chalcogenide halides and allow us to correlate the evolution of chemical bonding and structure with variability of the topological properties, although materials design should not be regarded as a building blocks set. Over the past decade, material discoveries have unearthed a plethora of topological properties, and bismuth is very fertile as a progenitor of a rich palette of exotic quantum materials, ranging from strong and weak 3D and crystalline topological insulators over topological metals and semimetals to magnetic topological insulators, while preserving the general layered structure motif.
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Affiliation(s)
- Anna Isaeva
- Faculty of Physics, Technische Universität Dresden, 01062 Dresden, Germany.,Leibniz IFW Dresden, Institute for Solid-State and Materials Research, Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Michael Ruck
- Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, 01062 Dresden, Germany.,Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Strasse 40, 01187 Dresden, Germany
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16
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Ni D, Guo S, Powderly KM, Zhong R, Cava RJ. A high-pressure phase with a non-centrosymmetric crystal structure in the PbSe–PbBr2 system. J SOLID STATE CHEM 2019. [DOI: 10.1016/j.jssc.2019.120982] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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17
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Dong YM, Zheng DX, Wang J. Cooper instability generated by attractive fermion-fermion interaction in the two-dimensional semi-Dirac semimetals. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:275601. [PMID: 30921787 DOI: 10.1088/1361-648x/ab142d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cooper instability (CI) associated with superconductivity in the two-dimensional semi-Dirac semimetals is attentively studied in the presence of attractive Cooper-pairing interaction, which is the projection of an attractive fermion-fermion interaction. Performing the standard renormalization group analysis shows that the Cooper theorem is violated at zero chemical potential but instead CI can be generated only if the absolute strength of fermion-fermion coupling exceeds certain critical value and transfer momentum is restricted to a confined region, which is determined by the initial conditions. Rather, the Cooper theorem would be instantly restored once a finite chemical potential is introduced and thus a chemical potential-tuned phase transition is expected. Additionally, we briefly examine the effects of impurity scatterings on the CI at zero chemical potential, which in principle are harmful to CI although they can enhance the density of states of systems. Furthermore, the influence of competition between a finite chemical potential and impurities upon the CI is also simply investigated. These results are expected to provide instructive clues for exploring unconventional superconductors in the kinds of semimetals.
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Affiliation(s)
- Yao-Ming Dong
- Department of Physics, Tianjin University, Tianjin 300072, People's Republic of China
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18
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Rajaji V, Janaky S, Sarma SC, Peter SC, Narayana C. Pressure induced topological and structural phase transitions in 1T-TiSe 2: a Raman study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:165401. [PMID: 30677001 DOI: 10.1088/1361-648x/ab01bb] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
High pressure Raman spectroscopy studies on 1T-TiSe2 were carried out up to ~20.5 GPa. Based on the anomalies in phonon linewidth (lifetime) and phonon frequency of A 1g mode, we observe three transitions at ~2.5 GPa, ~6.0 GPa and ~15 GPa. The transitions at ~2.5 and ~6.0 GPa are the two topological phase transitions consistent with the theoretical prediction by Zhu et al in 1T-TiSe2 under pressure, namely, a topological trivial to non-trivial transition (Z 2 = 1) and topological non-trivial to trivial transition (Z 2 = 0). The trigonal (1T) phase of TiSe2 is stable up to ~15 GPa beyond which it undergoes structural transition as seen from the appearance of new Raman modes. There is a coexistence of the 1T and the new high-pressure phase up to ~19 GPa. The structural transition is completely reversible as seen from the appearance of 1T phase Raman spectra upon release of the pressure.
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Affiliation(s)
- V Rajaji
- Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India. School of Advanced Materials, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bangalore 560 064, India. Authors contributed equally to the paper
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19
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Lyu JK, Ji WX, Zhang SF, Zhang CW, Wang PJ. Strain-Tuned Topological Insulator and Rashba-Induced Anisotropic Momentum-Locked Dirac Cones in Two-Dimensional SeTe Monolayers. ACS APPLIED MATERIALS & INTERFACES 2018; 10:43962-43969. [PMID: 30474373 DOI: 10.1021/acsami.8b18582] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Rashba spin-orbit coupling (SOC) in topological insulators (TIs) is a very interesting phenomenon and has received extensive attention in two-dimensional (2D) materials. However, the coexistence of Rashba SOC and band topology, especially for materials with a square lattice, is still lacking. Here, by using first-principles calculations, we propose for the first time a SeTe monolayer as a 2D candidate with these novel properties. We find that the square lattice exhibits anisotropic band dispersions near the Fermi level and a Rashba effect related to large SOC and inversion asymmetry, which leads to a Dirac semimetal state. Another prominent feature is that SeTe can achieve a topological state under a tensile strain of only 1%, characterized by the Z2 invariant and helical edge states. Our findings demonstrate that SeTe is a promising material for novel electronic and spintronics applications.
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Affiliation(s)
- Ji-Kai Lyu
- School of Physics and Technology , University of Jinan , Jinan , Shandong 250022 , People's Republic of China
| | - Wei-Xiao Ji
- School of Physics and Technology , University of Jinan , Jinan , Shandong 250022 , People's Republic of China
| | - Shu-Feng Zhang
- School of Physics and Technology , University of Jinan , Jinan , Shandong 250022 , People's Republic of China
| | - Chang-Wen Zhang
- School of Physics and Technology , University of Jinan , Jinan , Shandong 250022 , People's Republic of China
| | - Pei-Ji Wang
- School of Physics and Technology , University of Jinan , Jinan , Shandong 250022 , People's Republic of China
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20
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Facio JI, Efremov D, Koepernik K, You JS, Sodemann I, van den Brink J. Strongly Enhanced Berry Dipole at Topological Phase Transitions in BiTeI. PHYSICAL REVIEW LETTERS 2018; 121:246403. [PMID: 30608737 DOI: 10.1103/physrevlett.121.246403] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Indexed: 06/09/2023]
Abstract
Transitions between topologically distinct electronic states have been predicted in different classes of materials and observed in some. A major goal is the identification of measurable properties that directly expose the topological nature of such transitions. Here, we focus on the giant Rashba material bismuth tellurium iodine which exhibits a pressure-driven phase transition between topological and trivial insulators in three dimensions. We demonstrate that this transition, which proceeds through an intermediate Weyl semimetallic state, is accompanied by a giant enhancement of the Berry curvature dipole which can be probed in transport and optoelectronic experiments. From first-principles calculations, we show that the Berry dipole-a vector along the polar axis of this material-has opposite orientations in the trivial and topological insulating phases and peaks at the insulator-to-Weyl critical points, at which the nonlinear Hall conductivity can increase by over 2 orders of magnitude.
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Affiliation(s)
- Jorge I Facio
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Dmitri Efremov
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Klaus Koepernik
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Jhih-Shih You
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
| | - Inti Sodemann
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzerstr. 38, 01187 Dresden, Germany
| | - Jeroen van den Brink
- Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany
- Department of Physics, Technical University Dresden, Helmholtzstr. 10, 01062 Dresden, Germany
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21
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Li L, Wang Y, Wang Z, Liu Y, Wang B. Topological Insulator GMR Straintronics for Low-Power Strain Sensors. ACS APPLIED MATERIALS & INTERFACES 2018; 10:28789-28795. [PMID: 30058327 DOI: 10.1021/acsami.8b09664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A quantum spin Hall insulator, i.e., topological insulator (TI), is a natural candidate for low-power electronics and spintronics because of its intrinsic dissipationless feature. Recent density functional theory and scanning tunneling spectroscopy experiments show that the mechanical strain allows dynamic, continuous, and reversible modulations of the topological surface states within the topological phase and hence opens prospects for TI straintronics. Here, we combine the mechanical strain and the giant magnetoresistance (GMR) of a ferromagnet-TI (FM-TI) junction to construct a novel TI GMR straintronics device. Such a FM-strained-FM-TI junction permits several energy spectral ranges for 100% GMR and a robust strain-controllable magnetic switch. Beyond the 100% GMR energy range, we observe a strain-modulated oscillating GMR, which is an alternative hallmark of the Fabry-Pérot quantum interference of Dirac surface states. These strain-sensitive GMR responses indicate that FM-strained-FM-TI junctions are very favorable for practical applications for low-power nanoscale strain sensors.
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Affiliation(s)
- Lingzhi Li
- School of Engineering , Sun Yat-sen University , Guangzhou 510006 , China
| | - Yunhua Wang
- Sino-French Institute of Nuclear Engineering and Technology , Sun Yat-sen University , Zhuhai 519082 , China
- State Key Laboratory of Optoelectronic Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , China
| | - Zongtan Wang
- School of Engineering , Sun Yat-sen University , Guangzhou 510006 , China
| | - Yulan Liu
- School of Engineering , Sun Yat-sen University , Guangzhou 510006 , China
| | - Biao Wang
- Sino-French Institute of Nuclear Engineering and Technology , Sun Yat-sen University , Zhuhai 519082 , China
- State Key Laboratory of Optoelectronic Materials and Technologies , Sun Yat-sen University , Guangzhou 510275 , China
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22
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Owerre SA. Strain-induced topological magnon phase transitions: applications to kagome-lattice ferromagnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:245803. [PMID: 29741490 DOI: 10.1088/1361-648x/aac365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A common feature of topological insulators is that they are characterized by topologically invariant quantity such as the Chern number and the [Formula: see text] index. This quantity distinguishes a nontrivial topological system from a trivial one. A topological phase transition may occur when there are two topologically distinct phases, and it is usually defined by a gap closing point where the topologically invariant quantity is ill-defined. In this paper, we show that the magnon bands in the strained (distorted) kagome-lattice ferromagnets realize an example of a topological magnon phase transition in the realistic parameter regime of the system. When spin-orbit coupling (SOC) is neglected (i.e. no Dzyaloshinskii-Moriya interaction), we show that all three magnon branches are dispersive with no flat band, and there exists a critical point where tilted Dirac and semi-Dirac point coexist in the magnon spectra. The critical point separates two gapless magnon phases as opposed to the usual phase transition. Upon the inclusion of SOC, we realize a topological magnon phase transition point at the critical strain [Formula: see text], where D and J denote the perturbative SOC and the Heisenberg spin exchange interaction respectively. It separates two distinct topological magnon phases with different Chern numbers for [Formula: see text] and for [Formula: see text]. The associated anomalous thermal Hall conductivity develops an abrupt change at [Formula: see text], due to the divergence of the Berry curvature in momentum space. The proposed topological magnon phase transition is experimentally feasible by applying external perturbations such as uniaxial strain or pressure.
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Affiliation(s)
- S A Owerre
- Perimeter Institute for Theoretical Physics, 31 Caroline St. N., Waterloo, Ontario N2L 2Y5, Canada
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23
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Wang J. Role of four-fermion interaction and impurity in the states of two-dimensional semi-Dirac materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:125401. [PMID: 29345631 DOI: 10.1088/1361-648x/aaa8ce] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We study the effects of four-fermion interaction and impurity on the low-energy states of 2D semi-Dirac materials by virtue of the unbiased renormalization group approach. The coupled flow equations that govern the energy-dependent evolutions of all correlated interaction parameters are derived after taking into account one-loop corrections from the interplay between four-fermion interaction and impurity. Whether and how four-fermion interaction and impurity influence the low-energy properties of 2D semi-Dirac materials are discreetly explored and addressed attentively. After carrying out the standard renormalization group analysis, we find that both trivial insulating and nontrivial semimetal states are qualitatively stable against all four kinds of four-fermion interactions. However, while switching on both four-fermion interaction and impurity, certain insulator-semimetal phase transitions and the distance of Dirac nodal points can be respectively induced and modified due to their strong interplay and intimate competition. Moreover, several non-Fermi liquid behaviors that deviate from the conventional Fermi liquids are exhibited at the lowest-energy limit.
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Affiliation(s)
- Jing Wang
- Department of Physics, Tianjin University, Tianjin 300072, People's Republic of China. Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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24
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Rusinov IP, Golub P, Sklyadneva IY, Isaeva A, Menshchikova TV, Echenique PM, Chulkov EV. Chemically driven surface effects in polar intermetallic topological insulators A3Bi. Phys Chem Chem Phys 2018; 20:26372-26385. [PMID: 30303503 DOI: 10.1039/c8cp04016h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Surface electronic spectra, surface and bulk properties as well as the underlying chemical bonding characteristics in topological insulators with complex bonding patterns are considered for the example of cubic, polar intermetallics KNa2Bi, K3Bi and Rb3Bi (with the general formula A3Bi, A – alkali metal).
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Affiliation(s)
- I. P. Rusinov
- Tomsk State University
- Tomsk
- Russia
- St. Petersburg State University
- St. Petersburg
| | - P. Golub
- National University of Singapore
- 117575 Singapore
- Singapore
| | - I. Yu. Sklyadneva
- Tomsk State University
- Tomsk
- Russia
- Karlsruher Institut für Technologie
- Institut für Festkörperphysik
| | - A. Isaeva
- Technische Universität Dresden
- Dresden
- Germany
| | | | - P. M. Echenique
- Donostia International Physics Center (DIPC)
- 20018 San Sebastián/Donostia
- Spain
- Departamento de Física de Materiales
- Facultad de Ciencias Químicas
| | - E. V. Chulkov
- Tomsk State University
- Tomsk
- Russia
- St. Petersburg State University
- St. Petersburg
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25
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Jin KH, Jhi SH, Liu F. Nanostructured topological state in bismuth nanotube arrays: inverting bonding-antibonding levels of molecular orbitals. NANOSCALE 2017; 9:16638-16644. [PMID: 29087421 DOI: 10.1039/c7nr05325h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We demonstrate a new class of nanostructured topological materials that exhibit a topological quantum phase arising from nanoscale structural motifs. Based on first-principles calculations, we show that an array of bismuth nanotubes (Bi-NTs), a superlattice of Bi-NTs with periodicity in the order of tube diameter, behaves as a nanostructured two-dimensional (2D) quantum spin Hall (QSH) insulator, as confirmed from the calculated band topology and 1D helical edge states. The underpinning mechanism of the QSH phase in the Bi-NT array is revealed to be inversion of bonding-antibonding levels of molecular orbitals of constituent nanostructural elements in place of atomic-orbital band inversion in conventional QSH insulators. The quantized edge conductance of the QSH phase in a Bi-NT array can be more easily isolated from bulk contributions and their properties can be highly tuned by tube size, representing distinctive advantages of nanostructured topological phases. Our finding opens a new avenue for topological materials by extending topological phases into nanomaterials with molecular-orbital-band inversion.
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Affiliation(s)
- Kyung-Hwan Jin
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, UT 84112, USA.
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26
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Bahramy MS, Ogawa N. Bulk Rashba Semiconductors and Related Quantum Phenomena. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605911. [PMID: 28370556 DOI: 10.1002/adma.201605911] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/15/2017] [Indexed: 06/07/2023]
Abstract
Bithmuth tellurohalides BiTeX (X = Cl, Br and I) are model examples of bulk Rashba semiconductors, exhibiting a giant Rashba-type spin splitting among their both valence and conduction bands. Extensive spectroscopic and transport experiments combined with the state-of-the-art first-principles calculations have revealed many unique quantum phenomena emerging from the bulk Rashba effect in these systems. The novel features such as the exotic inter- and intra-band optical transitions, enhanced magneto-optical response, divergent orbital dia-/para-magnetic susceptibility and helical spin textures with a nontrivial Berry's phase in the momentum space are among the salient discoveries, all arising from this effect. Also, it is theoretically proposed and indications have been experimentally reported that bulk Rashba semiconductors such as BiTeI have the capability of becoming a topological insulator under the application of a hydrostatic pressure. Here, we overview these studies and show that BiTeX are an ideal platform to explore the next aspects of quantum matter, which could ultimately be utilized to create spintronic devices with novel functionalities.
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Affiliation(s)
- Mohammad Saeed Bahramy
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Naoki Ogawa
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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27
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Murakami S, Hirayama M, Okugawa R, Miyake T. Emergence of topological semimetals in gap closing in semiconductors without inversion symmetry. SCIENCE ADVANCES 2017; 3:e1602680. [PMID: 28508068 PMCID: PMC5429037 DOI: 10.1126/sciadv.1602680] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/07/2017] [Indexed: 05/02/2023]
Abstract
A band gap for electronic states in crystals governs various properties of solids, such as transport, optical, and magnetic properties. Its estimation and control have been an important issue in solid-state physics. The band gap can be controlled externally by various parameters, such as pressure, atomic compositions, and external field. Sometimes, the gap even collapses by tuning some parameter. In the field of topological insulators, this closing of the gap at a time-reversal invariant momentum indicates a band inversion, that is, it leads to a topological phase transition from a normal insulator to a topological insulator. We show, through an exhaustive study on possible space groups, that the gap closing in inversion-asymmetric crystals is universal, in the sense that the gap closing always leads either to a Weyl semimetal or to a nodal-line semimetal. We consider three-dimensional spinful systems with time-reversal symmetry. The space group of the system and the wave vector at the gap closing uniquely determine which possibility occurs and where the gap-closing points or lines lie in the wave vector space after the closing of the gap. In particular, we show that an insulator-to-insulator transition never happens, which is in sharp contrast to inversion-symmetric systems.
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Affiliation(s)
- Shuichi Murakami
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
- Tokodai Institute for Element Strategy, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
- Corresponding author.
| | - Motoaki Hirayama
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
- Tokodai Institute for Element Strategy, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Ryo Okugawa
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Takashi Miyake
- Research Center for Computational Design of Advanced Functional Materials, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8568, Japan
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28
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Qi Y, Shi W, Naumov PG, Kumar N, Sankar R, Schnelle W, Shekhar C, Chou FC, Felser C, Yan B, Medvedev SA. Topological Quantum Phase Transition and Superconductivity Induced by Pressure in the Bismuth Tellurohalide BiTeI. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605965. [PMID: 28262997 DOI: 10.1002/adma.201605965] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/12/2017] [Indexed: 06/06/2023]
Abstract
A pressure-induced topological quantum phase transition has been theoretically predicted for the semiconductor bismuth tellurohalide BiTeI with giant Rashba spin splitting. In this work, evolution of the electrical transport properties in BiTeI and BiTeBr is investigated under high pressure. The pressure-dependent resistivity in a wide temperature range passes through a minimum at around 3 GPa, indicating the predicted topological quantum phase transition in BiTeI. Superconductivity is observed in both BiTeI and BiTeBr, while resistivity at higher temperatures still exhibits semiconducting behavior. Theoretical calculations suggest that superconductivity may develop from the multivalley semiconductor phase. The superconducting transition temperature, Tc , increases with applied pressure and reaches a maximum value of 5.2 K at 23.5 GPa for BiTeI (4.8 K at 31.7 GPa for BiTeBr), followed by a slow decrease. The results demonstrate that BiTeX (X = I, Br) compounds with nontrivial topology of electronic states display new ground states upon compression.
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Affiliation(s)
- Yanpeng Qi
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Wujun Shi
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 200031, China
| | - Pavel G Naumov
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
- Shubnikov Institute of Crystallography of Federal Scientific Research Centre "Crystallography and Photonics", Russian Academy of Sciences, Moscow, 119333, Russia
| | - Nitesh Kumar
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Raman Sankar
- Institute of Physics, Academia Sinica, Taipei, 10617, Taiwan
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Walter Schnelle
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Chandra Shekhar
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Fang-Cheng Chou
- Center for Condensed Matter Sciences, National Taiwan University, Taipei, 10617, Taiwan
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
| | - Binghai Yan
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
- School of Physical Science and Technology, ShanghaiTech University, Shanghai, 200031, China
- Max Planck Institute for the Physics of Complex Systems, Dresden, 01187, Germany
| | - Sergey A Medvedev
- Max Planck Institute for Chemical Physics of Solids, Dresden, 01187, Germany
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29
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Zhang SJ, Ji WX, Zhang CW, Li P, Wang PJ. Two-Dimensional Large Gap Topological Insulators with Tunable Rashba Spin-Orbit Coupling in Group-IV films. Sci Rep 2017; 7:45923. [PMID: 28368035 PMCID: PMC5377469 DOI: 10.1038/srep45923] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 03/06/2017] [Indexed: 01/20/2023] Open
Abstract
The coexistence of nontrivial topology and giant Rashba splitting, however, has rare been observed in two-dimensional (2D) films, limiting severely its potential applications at room temperature. Here, we through first-principles calculations to propose a series of inversion-asymmetric group-IV films, ABZ2 (A ≠ B = Si, Ge, Sn, Pb; Z = F, Cl, Br), whose stability are confirmed by phonon spectrum calculations. The analyses of electronic structures reveal that they are intrinsic 2D TIs with a bulk gap as large as 0.74 eV, except for GeSiF2, SnSiCl2, GeSiCl2 and GeSiBr2 monolayers which can transform from normal to topological phases under appropriate tensile strain of 4, 4, 5, and 4%, respectively. The nontrivial topology is identified by Z2 topological invariant together with helical edge states, as well as the berry curvature of these systems. Another prominent intriguing feature is the giant Rashba spin splitting with a magnitude reaching 0.15 eV, the largest value reported in 2D films so far. The tunability of Rashba SOC and band topology can be realized through achievable compressive/tensile strains (−4 ~ 6%). Also, the BaTe semiconductor is an ideal substrate for growing ABZ2 films without destroying their nontrivial topology.
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Affiliation(s)
- Shou-Juan Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Wei-Xiao Ji
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Chang-Wen Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Ping Li
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Pei-Ji Wang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
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30
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VanGennep D, Linscheid A, Jackson DE, Weir ST, Vohra YK, Berger H, Stewart GR, Hennig RG, Hirschfeld PJ, Hamlin JJ. Pressure-induced superconductivity in the giant Rashba system BiTeI. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:09LT02. [PMID: 28004645 DOI: 10.1088/1361-648x/aa5567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
At ambient pressure, BiTeI exhibits a giant Rashba splitting of the bulk electronic bands. At low pressures, BiTeI undergoes a transition from trivial insulator to topological insulator. At still higher pressures, two structural transitions are known to occur. We have carried out a series of electrical resistivity and AC magnetic susceptibility measurements on BiTeI at pressure up to ∼40 GPa in an effort to characterize the properties of the high-pressure phases. A previous calculation found that the high-pressure orthorhombic P4/nmm structure BiTeI is a metal. We find that this structure is superconducting with T c values as high as 6 K. AC magnetic susceptibility measurements support the bulk nature of the superconductivity. Using electronic structure and phonon calculations, we compute T c and find that our data is consistent with phonon-mediated superconductivity.
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Affiliation(s)
- D VanGennep
- Department of Physics, University of Florida, Gainesville, FL 32611, United States of America
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31
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Łepkowski SP, Bardyszewski W. Topological phase transition and evolution of edge states in In-rich InGaN/GaN quantum wells under hydrostatic pressure. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:055702. [PMID: 27941228 DOI: 10.1088/1361-648x/29/5/055702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Combining the k · p method with the third-order elasticity theory, we perform a theoretical study of the pressure-induced topological phase transition and the pressure evolution of topologically protected edge states in InN/GaN and In-rich InGaN/GaN quantum wells. We show that for a certain range of the quantum well parameters, thanks to a negative band gap pressure coefficient, it is possible to continuously drive the system from the normal insulator state through the topological insulator into the semimetal phase. The critical pressure for the topological phase transition depends not only on the quantum well thickness but also on the width of the Hall bar, which determines the coupling between the edge states localized at the opposite edges. We also find that in narrow Hall bar structures, near the topological phase transition, a significant Rashba-type spin splitting of the lower and upper branches of the edge state dispersion curve appears. This effect originates from the lack of the mirror symmetry of the quantum well potential caused by the built-in electric field, and can be suppressed by increasing the Hall bar width. When the pressure increases, the energy dispersion of the edge states becomes more parabolic-like and the spin splitting decreases. A further increase of pressure leads to the transition to a semimetal phase, which occurs due to the closure of the indirect 2D bulk band gap. The difference between the critical pressure at which the system becomes semimetallic, and the pressure for the topological phase transition, correlates with the variation of the pressure coefficient of the band gap in the normal insulator state.
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Affiliation(s)
- S P Łepkowski
- Institute of High Pressure Physics 'Unipress', Polish Academy of Sciences, ul. Sokołowska 29/37, 01-142 Warszawa, Poland
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32
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Superconductivity Bordering Rashba Type Topological Transition. Sci Rep 2017; 7:39699. [PMID: 28051188 PMCID: PMC5209719 DOI: 10.1038/srep39699] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 11/24/2016] [Indexed: 11/15/2022] Open
Abstract
Strong spin orbital interaction (SOI) can induce unique quantum phenomena such as topological insulators, the Rashba effect, or p-wave superconductivity. Combining these three quantum phenomena into a single compound has important scientific implications. Here we report experimental observations of consecutive quantum phase transitions from a Rashba type topological trivial phase to topological insulator state then further proceeding to superconductivity in a SOI compound BiTeI tuned via pressures. The electrical resistivity measurement with V shape change signals the transition from a Rashba type topological trivial to a topological insulator phase at 2 GPa, which is caused by an energy gap close then reopen with band inverse. Superconducting transition appears at 8 GPa with a critical temperature TC of 5.3 K. Structure refinements indicate that the consecutive phase transitions are correlated to the changes in the Bi–Te bond and bond angle as function of pressures. The Hall Effect measurements reveal an intimate relationship between superconductivity and the unusual change in carrier density that points to possible unconventional superconductivity.
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33
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Yang M, Luo YZ, Zeng MG, Shen L, Lu YH, Zhou J, Wang SJ, Sou IK, Feng YP. Pressure induced topological phase transition in layered Bi2S3. Phys Chem Chem Phys 2017; 19:29372-29380. [DOI: 10.1039/c7cp04583b] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report pressure induced topological phase transition in the lightest bismuth based chalcogenide binary component and its surface states.
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Affiliation(s)
- Ming Yang
- Institute of Materials Research and Engineering
- A*STAR
- 2 Fusionopolis Way
- Singapore 138634
- Singapore
| | - Yong Zheng Luo
- Department of Physics
- National University of Singapore
- 2 Science Drive 3
- Singapore 117551
- Singapore
| | - Ming Gang Zeng
- Department of Physics
- National University of Singapore
- 2 Science Drive 3
- Singapore 117551
- Singapore
| | - Lei Shen
- Department of Mechanical Engineering
- National University of Singapore
- 5 Engineering Drive 1
- Singapore 117608
- Singapore
| | - Yun Hao Lu
- School of Materials Science and Engineering
- Zhejiang University
- Hangzhou 310027
- China
| | - Jun Zhou
- Department of Physics
- National University of Singapore
- 2 Science Drive 3
- Singapore 117551
- Singapore
| | - Shi Jie Wang
- Institute of Materials Research and Engineering
- A*STAR
- 2 Fusionopolis Way
- Singapore 138634
- Singapore
| | - Iam Keong Sou
- Department of Physics
- The Hong Kong University of Science and Technology
- Hong Kong
- China
| | - Yuan Ping Feng
- Centre for Advanced 2D Materials and Graphene Research Centre
- National University of Singapore
- 6 Science Drive 2
- Singapore 117546
- Singapore
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34
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Antonius G, Louie SG. Temperature-Induced Topological Phase Transitions: Promoted versus Suppressed Nontrivial Topology. PHYSICAL REVIEW LETTERS 2016; 117:246401. [PMID: 28009189 DOI: 10.1103/physrevlett.117.246401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Indexed: 06/06/2023]
Abstract
Contrary to previous two-band model studies which find increasing temperature would induce a topological phase transition, we show here through first-principles calculations that the opposite is also realizable, depending on the material's full band structure and symmetry of the electron-phonon coupling potential. This finding explains recent experimental results by Wojek et al. [Nat. Commun. 6, 8463 (2015)NCAOBW2041-172310.1038/ncomms9463]. We show that the topological phase diagram of BiTl(S_{1-δ}Se_{δ})_{2} as a function of doping and temperature contains two distinct regions with nontrivial topology. In BiTlS_{2}, the phonons promote the topological phase at high temperature, while in BiTlSe_{2}, the system is driven back into the trivial phase.
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Affiliation(s)
- Gabriel Antonius
- Department of Physics, University of California at Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Steven G Louie
- Department of Physics, University of California at Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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35
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Butler CJ, Yang PY, Sankar R, Lien YN, Lu CI, Chang LY, Chen CH, Wei CM, Chou FC, Lin MT. Quasiparticle Scattering in the Rashba Semiconductor BiTeBr: The Roles of Spin and Defect Lattice Site. ACS NANO 2016; 10:9361-9369. [PMID: 27660852 DOI: 10.1021/acsnano.6b04109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Observations of quasiparticle interference have been used in recent years to examine exotic carrier behavior at the surfaces of emergent materials, connecting carrier dispersion and scattering dynamics to real-space features with atomic resolution. We observe quasiparticle interference in the strongly Rashba split 2DEG-like surface band found at the tellurium termination of BiTeBr and examine two mechanisms governing quasiparticle scattering: We confirm the suppression of spin-flip scattering by comparing measured quasiparticle interference with a spin-dependent elastic scattering model applied to the calculated spectral function. We also use atomically resolved STM maps to identify point defect lattice sites and spectro-microscopy imaging to discern their varying scattering strengths, which we understand in terms of the calculated orbital characteristics of the surface band. Defects on the Bi sublattice cause the strongest scattering of the predominantly Bi 6p derived surface band, with other defects causing nearly no scattering near the conduction band minimum.
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Affiliation(s)
| | | | | | | | | | - Luo-Yueh Chang
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | - Chia-Hao Chen
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
| | | | - Fang-Cheng Chou
- National Synchrotron Radiation Research Center , Hsinchu 30076, Taiwan
- Taiwan Consortium of Emergent Crystalline Materials (TCECM), National Science Council , Taipei 10622, Taiwan
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36
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Cheng C, Sun JT, Chen XR, Fu HX, Meng S. Nonlinear Rashba spin splitting in transition metal dichalcogenide monolayers. NANOSCALE 2016; 8:17854-17860. [PMID: 27714035 DOI: 10.1039/c6nr04235j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Single-layer transition-metal dichalcogenides (TMDs) such as MoS2 and MoSe2 exhibit unique electronic band structures ideal for hosting many exotic spin-orbital orderings. It has been widely accepted that Rashba spin splitting (RSS) is linearly proportional to the external field in heterostructure interfaces or to the potential gradient in polar materials. Surprisingly, an extraordinary nonlinear dependence of RSS is found in semiconducting TMD monolayers under a gate field. In contrast to small and constant RSS in polar materials, the potential gradient in non-polar TMDs gradually increases with the gate bias, resulting in nonlinear RSS with a Rashba coefficient an order-of-magnitude larger than the linear one. Most strikingly, under a large gate field MoSe2 demonstrates the largest anisotropic spin splitting among all known semiconductors to our knowledge. Based on the k·p model via symmetry analysis, we identify that the third-order contributions are responsible for the large nonlinear Rashba splitting. The gate tunable spin splitting found in semiconducting pristine TMD monolayers promises future spintronics applications in that spin polarized electrons can be generated by external gating in an experimentally accessible way.
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Affiliation(s)
- Cai Cheng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. and College of Physical Science and Technology, Sichuan University, Chengdu 610064, China.
| | - Jia-Tao Sun
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| | - Xiang-Rong Chen
- College of Physical Science and Technology, Sichuan University, Chengdu 610064, China.
| | - Hui-Xia Fu
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
| | - Sheng Meng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China. and School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China.
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37
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Di Sante D, Barone P, Stroppa A, Garrity KF, Vanderbilt D, Picozzi S. Intertwined Rashba, Dirac, and Weyl Fermions in Hexagonal Hyperferroelectrics. PHYSICAL REVIEW LETTERS 2016; 117:076401. [PMID: 27563977 DOI: 10.1103/physrevlett.117.076401] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Indexed: 06/06/2023]
Abstract
By means of density functional theory based calculations, we study the role of spin-orbit coupling in the new family of ABC hyperferroelectrics [Garrity, Rabe, and Vanderbilt Phys. Rev. Lett. 112, 127601 (2014)]. We unveil an extremely rich physics strongly linked to ferroelectric properties, ranging from the electric control of bulk Rashba effect to the existence of a three-dimensional topological insulator phase, with concomitant topological surface states even in the ultrathin film limit. Moreover, we predict that the topological transition, as induced by alloying, is followed by a Weyl semimetal phase of finite concentration extension, which is robust against disorder, putting forward hyperferroelectrics as promising candidates for spin-orbitronic applications.
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Affiliation(s)
- Domenico Di Sante
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, L'Aquila 67100, Italy
| | - Paolo Barone
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, L'Aquila 67100, Italy
- Graphene Labs, Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Alessandro Stroppa
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, L'Aquila 67100, Italy
| | - Kevin F Garrity
- Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg Maryland, 20899, USA
| | - David Vanderbilt
- Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
| | - Silvia Picozzi
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Via Vetoio, L'Aquila 67100, Italy
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38
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Qi S, Qiao Z, Deng X, Cubuk ED, Chen H, Zhu W, Kaxiras E, Zhang SB, Xu X, Zhang Z. High-Temperature Quantum Anomalous Hall Effect in n-p Codoped Topological Insulators. PHYSICAL REVIEW LETTERS 2016; 117:056804. [PMID: 27517787 DOI: 10.1103/physrevlett.117.056804] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Indexed: 06/06/2023]
Abstract
The quantum anomalous Hall effect (QAHE) is a fundamental quantum transport phenomenon that manifests as a quantized transverse conductance in response to a longitudinally applied electric field in the absence of an external magnetic field, and it promises to have immense application potential in future dissipationless quantum electronics. Here, we present a novel kinetic pathway to realize the QAHE at high temperatures by n-p codoping of three-dimensional topological insulators. We provide a proof-of-principle numerical demonstration of this approach using vanadium-iodine (V-I) codoped Sb_{2}Te_{3} and demonstrate that, strikingly, even at low concentrations of ∼2% V and ∼1% I, the system exhibits a quantized Hall conductance, the telltale hallmark of QAHE, at temperatures of at least ∼50 K, which is 3 orders of magnitude higher than the typical temperatures at which it has been realized to date. The underlying physical factor enabling this dramatic improvement is tied to the largely preserved intrinsic band gap of the host system upon compensated n-p codoping. The proposed approach is conceptually general and may shed new light in experimental realization of high-temperature QAHE.
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Affiliation(s)
- Shifei Qi
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- School of Chemistry and Materials Science, Shanxi Normal University, Linfen, Shanxi 041004, China
| | - Zhenhua Qiao
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xinzhou Deng
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ekin D Cubuk
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Hua Chen
- Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Wenguang Zhu
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Efthimios Kaxiras
- School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA
| | - S B Zhang
- Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180-3590, USA
| | - Xiaohong Xu
- School of Chemistry and Materials Science, Shanxi Normal University, Linfen, Shanxi 041004, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
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39
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Tan LZ, Rappe AM. Enhancement of the Bulk Photovoltaic Effect in Topological Insulators. PHYSICAL REVIEW LETTERS 2016; 116:237402. [PMID: 27341257 DOI: 10.1103/physrevlett.116.237402] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Indexed: 06/06/2023]
Abstract
We investigate the shift current bulk photovoltaic response of materials close to a band inversion topological phase transition. We find that the bulk photocurrent reverses direction across the band inversion transition, and that its magnitude is enhanced in the vicinity of the phase transition. These results are demonstrated with first principles density functional theory calculations of BiTeI and CsPbI_{3} under hydrostatic pressure, and explained with an analytical model, suggesting that this phenomenon remains robust across disparate material systems.
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Affiliation(s)
- Liang Z Tan
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
| | - Andrew M Rappe
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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40
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Shimizu S, Bahramy MS, Iizuka T, Ono S, Miwa K, Tokura Y, Iwasa Y. Enhanced thermopower in ZnO two-dimensional electron gas. Proc Natl Acad Sci U S A 2016; 113:6438-43. [PMID: 27222585 PMCID: PMC4988615 DOI: 10.1073/pnas.1525500113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Control of dimensionality has proven to be an effective way to manipulate the electronic properties of materials, thereby enabling exotic quantum phenomena, such as superconductivity, quantum Hall effects, and valleytronic effects. Another example is thermoelectricity, which has been theoretically proposed to be favorably controllable by reducing the dimensionality. Here, we verify this proposal by performing a systematic study on a gate-tuned 2D electron gas (2DEG) system formed at the surface of ZnO. Combining state-of-the-art electric-double-layer transistor experiments and realistic tight-binding calculations, we show that, for a wide range of carrier densities, the 2DEG channel comprises a single subband, and its effective thickness can be reduced to [Formula: see text] 1 nm at sufficiently high gate biases. We also demonstrate that the thermoelectric performance of the 2DEG region is significantly higher than that of bulk ZnO. Our approach opens up a route to exploit the peculiar behavior of 2DEG electronic states and realize thermoelectric devices with advanced functionalities.
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Affiliation(s)
- Sunao Shimizu
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan;
| | - Mohammad Saeed Bahramy
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan; Quantum Phase Electronics Center and Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
| | - Takahiko Iizuka
- Quantum Phase Electronics Center and Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
| | - Shimpei Ono
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan; Central Research Institute of Electric Power Industry, Yokosuka, Kanagawa 240-0196, Japan
| | - Kazumoto Miwa
- Central Research Institute of Electric Power Industry, Yokosuka, Kanagawa 240-0196, Japan
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan; Quantum Phase Electronics Center and Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
| | - Yoshihiro Iwasa
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan; Quantum Phase Electronics Center and Department of Applied Physics, University of Tokyo, Bunkyo, Tokyo 113-8656, Japan
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41
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Brosco V, Benfatto L, Cappelluti E, Grimaldi C. Unconventional dc Transport in Rashba Electron Gases. PHYSICAL REVIEW LETTERS 2016; 116:166602. [PMID: 27152815 DOI: 10.1103/physrevlett.116.166602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Indexed: 06/05/2023]
Abstract
We discuss the transport properties of a disordered two-dimensional electron gas with strong Rashba spin-orbit coupling. We show that in the high-density regime where the Fermi energy overcomes the energy associated with spin-orbit coupling, dc transport is accurately described by a standard Drude's law, due to a nontrivial compensation between the suppression of backscattering and the relativistic correction to the quasiparticle velocity. On the contrary, when the system enters the opposite dominant spin-orbit regime, Drude's paradigm breaks down and the dc conductivity becomes strongly sensitive to the spin-orbit coupling strength, providing a suitable tool to test the entanglement between spin and charge degrees of freedom in these systems.
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Affiliation(s)
- Valentina Brosco
- ISC-CNR and Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Lara Benfatto
- ISC-CNR and Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Emmanuele Cappelluti
- ISC-CNR and Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - Claudio Grimaldi
- Laboratory of Physics of Complex Matter, Ecole Polytechnique Fédérale de Lausanne, Station 3, CH-1015 Lausanne, Switzerland
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Li SS, Ji WX, Zhang CW, Hu SJ, Li P, Wang PJ, Zhang BM, Cao CL. Robust Room-Temperature Quantum Spin Hall Effect in Methyl-functionalized InBi honeycomb film. Sci Rep 2016; 6:23242. [PMID: 26997163 PMCID: PMC4800414 DOI: 10.1038/srep23242] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 03/02/2016] [Indexed: 11/09/2022] Open
Abstract
Two-dimensional (2D) group-III-V honeycomb films have attracted significant interest for their potential application in fields of quantum computing and nanoelectronics. Searching for 2D III-V films with high structural stability and large-gap are crucial for the realizations of dissipationless transport edge states using quantum spin Hall (QSH) effect. Based on first-principles calculations, we predict that the methyl-functionalized InBi monolayer (InBiCH3) has no dynamic instability, and hosts QSH state with a band gap as large as 0.29 eV, exhibiting an interesting electronic behavior viable for room-temperature applications. The topological characteristic is confirmed by s-pxy band inversion, topological invariant Z2 number, and the time-reversal symmetry protected helical edge states. Noticeably, the QSH states are tunable and robust against the mechanical strain, electric field and different levels of methyl coverages. We also find that InBiCH3 supported on h-BN substrate maintains a nontrivial QSH state, which harbors the edge states lying within the band gap of substrate. These findings demonstrate that the methyl-functionalized III-V films may be a good QSH platform for device design and fabrication in spintronics.
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Affiliation(s)
- Sheng-Shi Li
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China.,School of Physics, State Key laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, People's Republic of China
| | - Wei-Xiao Ji
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Chang-Wen Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Shu-Jun Hu
- School of Physics, State Key laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, People's Republic of China
| | - Ping Li
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Pei-Ji Wang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Bao-Min Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
| | - Chong-Long Cao
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People's Republic of China
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Abstract
Ferroelectricity and band topology are two extensively studied yet distinct properties of insulators. Nonetheless, their coexistence has never been observed in a single material. Using first-principles calculations, we demonstrate that a noncentrosymmetric perovskite structure of CsPbI3 allows for the simultaneous presence of ferroelectric and topological orders with appropriate strain engineering. Metallic topological surface states create an intrinsic short-circuit condition, helping stabilize bulk polarization. Exploring diverse structural phases of CsPbI3 under pressure, we identify that the key structural feature for achieving a ferroelectric topological insulator is to suppress PbI6 cage rotation in the perovskite structure, which could be obtained via strain engineering. Ferroelectric control over the density of topological surface states provides a new paradigm for device engineering, such as perfect-focusing Veselago lens and spin-selective electron collimator. Our results suggest that CsPbI3 is a simple model system for ferroelectric topological insulators, enabling future studies exploring the interplay between conventional symmetry-breaking and topological orders and their novel applications in electronics and spintronics.
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Affiliation(s)
- Shi Liu
- Geophysical Laboratory, Carnegie Institution for Science , Washington, DC 20015, United States
| | - Youngkuk Kim
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104-6323, United States
| | - Liang Z Tan
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104-6323, United States
| | - Andrew M Rappe
- The Makineni Theoretical Laboratories, Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104-6323, United States
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Zhang RW, Zhang CW, Ji WX, Li SS, Yan SS, Li P, Wang PJ. Functionalized Thallium Antimony Films as Excellent Candidates for Large-Gap Quantum Spin Hall Insulator. Sci Rep 2016; 6:21351. [PMID: 26882865 PMCID: PMC4756673 DOI: 10.1038/srep21351] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/22/2016] [Indexed: 11/26/2022] Open
Abstract
Group III-V films are of great importance for their potential application in spintronics and quantum computing. Search for two-dimensional III-V films with a nontrivial large-gap are quite crucial for the realization of dissipationless transport edge channels using quantum spin Hall (QSH) effects. Here we use first-principles calculations to predict a class of large-gap QSH insulators in functionalized TlSb monolayers (TlSbX2; (X = H, F, Cl, Br, I)), with sizable bulk gaps as large as 0.22~0.40 eV. The QSH state is identified by Z2 topological invariant together with helical edge states induced by spin-orbit coupling (SOC). Noticeably, the inverted band gap in the nontrivial states can be effectively tuned by the electric field and strain. Additionally, these films on BN substrate also maintain a nontrivial QSH state, which harbors a Dirac cone lying within the band gap. These findings may shed new light in future design and fabrication of QSH insulators based on two-dimensional honeycomb lattices in spintronics.
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Affiliation(s)
- Run-wu Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People’s Republic of China
| | - Chang-wen Zhang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People’s Republic of China
| | - Wei-xiao Ji
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People’s Republic of China
| | - Sheng-shi Li
- School of Physics, State Key laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, People’s Republic of China
| | - Shi-shen Yan
- School of Physics, State Key laboratory of Crystal Materials, Shandong University, Jinan, Shandong, 250100, People’s Republic of China
| | - Ping Li
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People’s Republic of China
| | - Pei-ji Wang
- School of Physics and Technology, University of Jinan, Jinan, Shandong, 250022, People’s Republic of China
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Mirror-symmetry protected non-TRIM surface state in the weak topological insulator Bi2TeI. Sci Rep 2016; 6:20734. [PMID: 26864814 PMCID: PMC4749960 DOI: 10.1038/srep20734] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 01/06/2016] [Indexed: 11/10/2022] Open
Abstract
Strong topological insulators (TIs) support topological surfaces states on any crystal surface. In contrast, a weak, time-reversal-symmetry-driven TI with at least one non-zero v1, v2, v3 ℤ2 index should host spin-locked topological surface states on the surfaces that are not parallel to the crystal plane with Miller indices (v1 v2 v3). On the other hand, mirror symmetry can protect an even number of topological states on the surfaces that are perpendicular to a mirror plane. Various symmetries in a bulk material with a band inversion can independently preordain distinct crystal planes for realization of topological states. Here we demonstrate the first instance of coexistence of both phenomena in the weak 3D TI Bi2TeI which (v1 v2 v3) surface hosts a gapless spin-split surface state protected by the crystal mirror-symmetry. The observed topological state has an even number of crossing points in the directions of the 2D Brillouin zone due to a non-TRIM bulk-band inversion. Our findings shed light on hitherto uncharted features of the electronic structure of weak topological insulators and open up new vistas for applications of these materials in spintronics.
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Sorb YA, Rajaji V, Malavi PS, Subbarao U, Halappa P, Peter SC, Karmakar S, Narayana C. Pressure-induced electronic topological transition in Sb2S3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:015602. [PMID: 26656791 DOI: 10.1088/0953-8984/28/1/015602] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We report the high-pressure vibrational properties and a pressure-induced electronic topological transition in the wide bandgap semiconductor Sb2S3 (E g = 1.7-1.8 eV) using Raman spectroscopy, resistivity and x-ray diffraction (XRD) studies. In this report, high-pressure Raman spectroscopy and resistivity studies of Sb2S3 have been carried out to 22 GPa and 11 GPa, respectively. We observed the softening of phonon modes [Formula: see text], [Formula: see text] and B 2g and a sharp anomaly in their line widths at 4 GPa. The resistivity studies corroborate this anomaly around similar pressures. The changes in resistivity as well as Raman line widths can be ascribed to the strong phonon-phonon coupling, indicating clear evidence of isostructural electronic topological transition in Sb2S3. The previously reported pressure dependence of a/c ratio plot obtained also showed a minimum at ~5 GPa consistent with our high-pressure Raman and resistivity results.
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Affiliation(s)
- Y A Sorb
- Chemistry and Physics of Materials Unit, JNCASR, Jakkur, Bangalore 560 064, India
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Zhang SJ, Ji WX, Zhang CW, Li SS, Li P, Ren MJ, Wang PJ. Hydrogenated group-IV binary monolayers: a new family of inversion-asymmetric topological insulators. RSC Adv 2016. [DOI: 10.1039/c6ra14140d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Band topology and Rashba spin splitting (RSS) are two extensively explored exotic properties in condensed matter physics.
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Affiliation(s)
- Shou-juan Zhang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Wei-xiao Ji
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Chang-wen Zhang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Sheng-shi Li
- School of Physics
- State Key Laboratory of Crystal Materials
- Shandong University
- Jinan
- People's Republic of China
| | - Ping Li
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Miao-juan Ren
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Pei-ji Wang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
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48
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Zhou L, Kou L, Sun Y, Felser C, Hu F, Shan G, Smith SC, Yan B, Frauenheim T. New Family of Quantum Spin Hall Insulators in Two-dimensional Transition-Metal Halide with Large Nontrivial Band Gaps. NANO LETTERS 2015; 15:7867-7872. [PMID: 26524118 DOI: 10.1021/acs.nanolett.5b02617] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Topological insulators (TIs) are promising for achieving dissipationless transport devices due to the robust gapless states inside the insulating bulk gap. However, currently realized two-dimensional (2D) TIs, quantum spin Hall (QSH) insulators, suffer from ultrahigh vacuum and extremely low temperature. Thus, seeking for desirable QSH insulators with high feasibility of experimental preparation and large nontrivial gap is of great importance for wide applications in spintronics. On the basis of the first-principles calculations, we predict a novel family of 2D QSH insulators in transition-metal halide MX (M = Zr, Hf; X = Cl, Br, and I) monolayers, especially, which is the first case based on transition-metal halide-based QSH insulators. MX family has the large nontrivial gaps of 0.12-0.4 eV, comparable with bismuth (111) bilayer (0.2 eV), stanene (0.3 eV), and larger than ZrTe5 (0.1 eV) monolayers and graphene-based sandwiched heterstructures (30-70 meV). Their corresponding 3D bulk materials are weak topological insulators from stacking QSH layers, and some of bulk compounds have already been synthesized in experiment. The mechanism for 2D QSH effect in this system originates from a novel d-d band inversion, significantly different from conventional band inversion between s-p, p-p, or d-p orbitals. The realization of pure layered MX monolayers may be prepared by exfoliation from their 3D bulk phases, thus holding great promise for nanoscale device applications and stimulating further efforts on transition metal-based QSH materials.
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Affiliation(s)
- Liujiang Zhou
- Bremen Center for Computational Materials Science, University of Bremen , Am Falturm 1, 28359 Bremen, Germany
| | - Liangzhi Kou
- Integrated Materials Design Centre, School of Chemical Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Yan Sun
- Max Planck Institute for Chemical Physics of Solids , Noethnitzer Strasse 40, 01187 Dresden, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids , Noethnitzer Strasse 40, 01187 Dresden, Germany
| | - Feiming Hu
- Bremen Center for Computational Materials Science, University of Bremen , Am Falturm 1, 28359 Bremen, Germany
| | - Guangcun Shan
- Department of Physics and Materials Science and Center for Functional Photonics, City University of Hong Kong , Kowloon Tong, Hong Kong SAR
| | - Sean C Smith
- Integrated Materials Design Centre, School of Chemical Engineering, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Binghai Yan
- Max Planck Institute for Chemical Physics of Solids , Noethnitzer Strasse 40, 01187 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems , Noethnitzer Strasse 38, 01187 Dresden, Germany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen , Am Falturm 1, 28359 Bremen, Germany
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Yan YJ, Ren MQ, Liu X, Huang ZC, Jiang J, Fan Q, Miao J, Xie BP, Xiang F, Wang X, Zhang T, Feng DL. Scanning tunneling microscopy study of the possible topological surface states in BiTeCl. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2015; 27:475004. [PMID: 26491022 DOI: 10.1088/0953-8984/27/47/475004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recently, the non-centrosymmetric bismuth tellurohalides such as BiTeCl are being studied as possible candidates for topological insulators. While some photoemission studies showed that BiTeCl is an inversion asymmetric topological insulator, others showed that it is a normal semiconductor with Rashba splitting. Meanwhile, first-principle calculations have failed to confirm the existence of topological surface states in BiTeCl so far. Therefore, the topological nature of BiTeCl requires further investigation. Here we report a low-temperature scanning tunneling microscopy study on the surface states of BiTeCl single crystals. On the tellurium (Te) -terminated surfaces with relatively low defect density, evidence for topological surface states is observed in the quasi-particle interference patterns, both in the anisotropy of the scattering vectors and the fast decay of the interference near the step edges. Meanwhile, on the samples with much higher defect densities, we observed surface states that behave differently. Our results may help to resolve the current controversy on the topological nature of BiTeCl.
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Affiliation(s)
- Y J Yan
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, People' Republic of China
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50
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Sodemann I, Fu L. Quantum Nonlinear Hall Effect Induced by Berry Curvature Dipole in Time-Reversal Invariant Materials. PHYSICAL REVIEW LETTERS 2015; 115:216806. [PMID: 26636867 DOI: 10.1103/physrevlett.115.216806] [Citation(s) in RCA: 160] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Indexed: 05/27/2023]
Abstract
It is well known that a nonvanishing Hall conductivity requires broken time-reversal symmetry. However, in this work, we demonstrate that Hall-like currents can occur in second-order response to external electric fields in a wide class of time-reversal invariant and inversion breaking materials, at both zero and twice the driving frequency. This nonlinear Hall effect has a quantum origin arising from the dipole moment of the Berry curvature in momentum space, which generates a net anomalous velocity when the system is in a current-carrying state. The nonlinear Hall coefficient is a rank-two pseudotensor, whose form is determined by point group symmetry. We discus optimal conditions to observe this effect and propose candidate two- and three-dimensional materials, including topological crystalline insulators, transition metal dichalcogenides, and Weyl semimetals.
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Affiliation(s)
- Inti Sodemann
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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