1
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Noguchi R, Kobayashi M, Kawaguchi K, Yamamori W, Aido K, Lin C, Tanaka H, Kuroda K, Harasawa A, Kandyba V, Cattelan M, Barinov A, Hashimoto M, Lu D, Ochi M, Sasagawa T, Kondo T. Robust Weak Topological Insulator in the Bismuth Halide Bi_{4}Br_{2}I_{2}. PHYSICAL REVIEW LETTERS 2024; 133:086602. [PMID: 39241706 DOI: 10.1103/physrevlett.133.086602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 07/09/2024] [Indexed: 09/09/2024]
Abstract
We apply a topological material design concept for selecting a bulk topology of 3D crystals by different van der Waals stackings of 2D topological insulator layers, and find a bismuth halide Bi_{4}Br_{2}I_{2} to be an ideal weak topological insulator (WTI) with the largest band gap (∼300 meV) among all the WTI candidates, by means of angle-resolved photoemission spectroscopy (ARPES), density functional theory (DFT) calculations, and resistivity measurements. Furthermore, we reveal that the topological surface state of a WTI is not "weak" but rather robust against external perturbations against the initial theoretical prediction by performing potassium deposition experiments. Our results vastly expand future opportunities for fundamental research and device applications with a robust WTI.
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Affiliation(s)
| | | | | | | | | | | | | | - Kenta Kuroda
- Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM), Hiroshima University, Higashi-hiroshima, Hiroshima 739-8526, Japan
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashi-hiroshima, Hiroshima 739-8526, Japan
| | | | | | | | | | | | | | - Masayuki Ochi
- Department of Physics, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
- Forefront Research Center, Osaka University, 1-1 Machikaneyama-cho, Toyonaka, Osaka 560-0043, Japan
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2
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Meng R, Pereira LMC, Van de Vondel J, Seo JW, Locquet JP, Houssa M. Large-Gap Quantum Spin Hall Insulators in Two-Dimensional Hafnium Halides: Unraveling the Impact of Strain and Substrate. ACS OMEGA 2024; 9:31890-31898. [PMID: 39072052 PMCID: PMC11270569 DOI: 10.1021/acsomega.4c03502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/22/2024] [Accepted: 06/27/2024] [Indexed: 07/30/2024]
Abstract
Two-dimensional (2D) topological insulators (TIs) or quantum spin Hall (QSH) insulators, characterized by insulating 2D electronic band structures and metallic helical edge states protected by time-reversal symmetry, offer a platform for realizing the quantum spin Hall effect, making them promising candidates for future spintronic devices and quantum computing. However, observing a high-temperature quantum spin Hall effect requires large-gap 2D TIs, and only a few 2D systems have been experimentally confirmed to possess this property. In this study, we employ first-principles calculations, combined with a structural search based on an evolutionary algorithm, to predict a class of 2D QSH insulators in hafnium halides, namely, HfF, HfCl, and HfBr with sizable band gaps of 0.12, 0.19, and 0.38 eV. Their topological nontrivial nature is confirmed by a Z2 invariant which equals to 1 and the presence of gapless edge states. Furthermore, the QSH effect in these materials remains robust under biaxial tensile strain of up to 10%, and the use of h-BN as a substrate effectively preserves the QSH states in these materials. Our findings pave the way for future theoretical and experimental investigations of 2D hafnium halides and their potential for realizing the QSH effect.
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Affiliation(s)
- Ruishen Meng
- KU
Leuven, Department of Physics
and Astronomy, Semiconductor Physics Laboratory, Leuven B-3001, Belgium
| | - Lino M. C. Pereira
- KU
Leuven, Department of Physics and Astronomy,
Quantum Solid-State Physics, Leuven B-3001, Belgium
| | - Joris Van de Vondel
- KU
Leuven, Department of Physics and Astronomy,
Quantum Solid-State Physics, Leuven B-3001, Belgium
| | - Jin Won Seo
- KU
Leuven, Department of Materials Engineering, Leuven B-3001, Belgium
| | - Jean-Pierre Locquet
- KU
Leuven, Department of Physics
and Astronomy, Semiconductor Physics Laboratory, Leuven B-3001, Belgium
| | - Michel Houssa
- KU
Leuven, Department of Physics
and Astronomy, Semiconductor Physics Laboratory, Leuven B-3001, Belgium
- imec, Leuven B-3001, Belgium
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3
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Xu YJ, Cao G, Li QY, Xue CL, Zhao WM, Wang QW, Dou LG, Du X, Meng YX, Wang YK, Gao YH, Jia ZY, Li W, Ji L, Li FS, Zhang Z, Cui P, Xing D, Li SC. Realization of monolayer ZrTe 5 topological insulators with wide band gaps. Nat Commun 2024; 15:4784. [PMID: 38839772 PMCID: PMC11153644 DOI: 10.1038/s41467-024-49197-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 05/28/2024] [Indexed: 06/07/2024] Open
Abstract
Two-dimensional topological insulators hosting the quantum spin Hall effect have application potential in dissipationless electronics. To observe the quantum spin Hall effect at elevated temperatures, a wide band gap is indispensable to efficiently suppress bulk conduction. Yet, most candidate materials exhibit narrow or even negative band gaps. Here, via elegant control of van der Waals epitaxy, we have successfully grown monolayer ZrTe5 on a bilayer graphene/SiC substrate. The epitaxial ZrTe5 monolayer crystalizes in two allotrope isomers with different intralayer alignments of ZrTe3 prisms. Our scanning tunneling microscopy/spectroscopy characterization unveils an intrinsic full band gap as large as 254 meV and one-dimensional edge states localized along the periphery of the ZrTe5 monolayer. First-principles calculations further confirm that the large band gap originates from strong spin-orbit coupling, and the edge states are topologically nontrivial. These findings thus provide a highly desirable material platform for the exploration of the high-temperature quantum spin Hall effect.
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Affiliation(s)
- Yong-Jie Xu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Guohua Cao
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, China
| | - Qi-Yuan Li
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Cheng-Long Xue
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Wei-Min Zhao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Qi-Wei Wang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Li-Guo Dou
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Xuan Du
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Yu-Xin Meng
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Yuan-Kun Wang
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Yu-Hang Gao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Zhen-Yu Jia
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
| | - Wei Li
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Lianlian Ji
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Fang-Sen Li
- Vacuum Interconnected Nanotech Workstation, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, China
- Hefei National Laboratory, Hefei, China
| | - Ping Cui
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, China.
- Hefei National Laboratory, Hefei, China.
| | - Dingyu Xing
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China
| | - Shao-Chun Li
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing, China.
- Hefei National Laboratory, Hefei, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, China.
- Jiangsu Provincial Key Laboratory for Nanotechnology, Nanjing University, Nanjing, China.
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4
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Gong Z, Lai X, Miao W, Zhong J, Shi Z, Shen H, Liu X, Li Q, Yang M, Zhuang J, Du Y. Br-Vacancies Induced Variable Ranging Hopping Conduction in High-Order Topological Insulator Bi 4Br 4. SMALL METHODS 2024:e2400517. [PMID: 38763921 DOI: 10.1002/smtd.202400517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 04/30/2024] [Indexed: 05/21/2024]
Abstract
The defects have a remarkable influence on the electronic structures and the electric transport behaviors of the matter, providing the additional means to engineering their physical properties. In this work, a comprehensive study on the effect of Br-vacancies on the electronic structures and transport behaviors in the high-order topological insulator Bi4Br4 is performed by the combined techniques of the scanning tunneling microscopy (STM), angle-resolved photoemission spectroscopy (ARPES), and physical properties measurement system along with the first-principle calculations. The STM results show the defects on the cleaved surface of a single crystal and reveal that the defects are correlated to the Br-vacancies with the support of the simulated STM images. The role of the Br-vacancies in the modulation of the band structures has been identified by ARPES spectra and the calculated energy-momentum dispersion. The relationship between the Br-vacancies and the semiconducting-like transport behaviors at low temperature has been established, implying a Mott variable ranging hopping conduction in Bi4Br4. The work not only resolves the unclear transport behaviors in this matter, but also paves a way to modulate the electric conduction path by the defects engineering.
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Affiliation(s)
- Zixin Gong
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Xingyu Lai
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Wenjing Miao
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Jingyuan Zhong
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Zhijian Shi
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Huayi Shen
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Xinqi Liu
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Qiyi Li
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Ming Yang
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Jincheng Zhuang
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
| | - Yi Du
- School of Physics, Beihang University, Haidian District, Beijing, 100191, China
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5
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Zhong J, Yang M, Wang J, Li Y, Liu C, Mu D, Liu Y, Cheng N, Shi Z, Yang L, Zhuang J, Du Y, Hao W. Observation of Anomalous Planar Hall Effect Induced by One-Dimensional Weak Antilocalization. ACS NANO 2024; 18:4343-4351. [PMID: 38277336 DOI: 10.1021/acsnano.3c10120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
The confinement of electrons in one-dimensional (1D) space highlights the prominence of the role of electron interactions or correlations, leading to a variety of fascinating physical phenomena. The quasi-1D electron states can exhibit a unique spin texture under spin-orbit interaction (SOI) and thus could generate a robust spin current by forbidden electron backscattering. Direct detection of such 1D spin or SOI information, however, is challenging due to complicated techniques. Here, we identify an anomalous planar Hall effect (APHE) in the magnetotransport of quasi-1D van der Waals (vdW) topological materials as exemplified by Bi4Br4, which arises from the quantum interference correction of 1D weak antilocalization (WAL) to the ordinary planar Hall effect and demonstrates a deviation from the usual sine and cosine curves. The occurrence of 1D WAL is correlated to the line-shape Fermi surface and persistent spin texture of (100) topological surface states of Bi4Br4, as revealed by both our angle-resolved photoemission spectroscopy and first-principles calculations. By generalizing the observation of APHE to other non-vdW bulk materials, this work provides a possible characteristic of magnetotransport for identifying the spin/SOI information and quantum interference behavior of 1D states in 3D topological material.
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Affiliation(s)
- Jingyuan Zhong
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Ming Yang
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Jianfeng Wang
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Yaqi Li
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
| | - Chen Liu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
| | - Dan Mu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yundan Liu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Ningyan Cheng
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China
| | - Zhixiang Shi
- School of Physics and Key Laboratory of the Ministry of Education, Southeast University, Nanjing 211189, People's Republic of China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - Jincheng Zhuang
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China
| | - Yi Du
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China
| | - Weichang Hao
- School of Physics, Beihang University, Haidian District, Beijing 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing 100191, China
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6
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Zhao W, Yang M, Xu R, Du X, Li Y, Zhai K, Peng C, Pei D, Gao H, Li Y, Xu L, Han J, Huang Y, Liu Z, Yao Y, Zhuang J, Du Y, Zhou J, Chen Y, Yang L. Topological electronic structure and spin texture of quasi-one-dimensional higher-order topological insulator Bi 4Br 4. Nat Commun 2023; 14:8089. [PMID: 38062024 PMCID: PMC10703900 DOI: 10.1038/s41467-023-43882-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 11/22/2023] [Indexed: 03/25/2024] Open
Abstract
The notion of topological insulators (TIs), characterized by an insulating bulk and conducting topological surface states, can be extended to higher-order topological insulators (HOTIs) hosting gapless modes localized at the boundaries of two or more dimensions lower than the insulating bulk. In this work, by performing high-resolution angle-resolved photoemission spectroscopy (ARPES) measurements with submicron spatial and spin resolution, we systematically investigate the electronic structure and spin texture of quasi-one-dimensional (1D) HOTI candidate Bi4Br4. In contrast to the bulk-state-dominant spectra on the (001) surface, we observe gapped surface states on the (100) surface, whose dispersion and spin-polarization agree well with our ab-initio calculations. Moreover, we reveal in-gap states connecting the surface valence and conduction bands, which is a signature of the hinge states inside the (100) surface gap. Our findings provide compelling evidence for the HOTI phase of Bi4Br4. The identification of the higher-order topological phase promises applications based on 1D spin-momentum locked current in electronic and spintronic devices.
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Affiliation(s)
- Wenxuan Zhao
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Ming Yang
- School of Physics, Beihang University, Beijing, 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, China
| | - Runzhe Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Xian Du
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Yidian Li
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Kaiyi Zhai
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Cheng Peng
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Ding Pei
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK
| | - Han Gao
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China
| | - Yiwei Li
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China
| | - Lixuan Xu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China
| | - Junfeng Han
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314001, Zhejiang province, China
| | - Yuan Huang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314001, Zhejiang province, China
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 200031, China
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing, 314001, Zhejiang province, China
| | - Jincheng Zhuang
- School of Physics, Beihang University, Beijing, 100191, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, China
| | - Yi Du
- School of Physics, Beihang University, Beijing, 100191, China.
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, 100191, China.
| | - Jinjian Zhou
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
| | - Yulin Chen
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU, UK.
- School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, 201210, China.
- ShanghaiTech Laboratory for Topological Physics, Shanghai, 200031, China.
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China.
- Frontier Science Center for Quantum Information, Beijing, 100084, China.
- Collaborative Innovation Center of Quantum Matter, Beijing, China.
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7
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Zhang Y, Zhang J, Yang W, Zhang H, Jia J. Engineering topological states in a two-dimensional honeycomb lattice. Phys Chem Chem Phys 2023; 25:25398-25407. [PMID: 37705503 DOI: 10.1039/d3cp03507g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/15/2023]
Abstract
In this work, we use first-principles calculations to determine the interplay between spin-orbit coupling (SOC) and magnetism which can not only generate a quantum anomalous Hall state but can also result in topologically trivial states although some honeycomb systems host large band gaps. By employing tight-binding model analysis, we have summarized two types of topologically trivial states: one is due to the coexistence of quadratic non-Dirac and linear Dirac bands in the same spin channel that act together destructively in magnetic materials (such as, CrBr3, CrCl3, and VBr3 monolayers); the other one is caused by the destructive coupling effect between two different spin channels due to small magnetic spin splitting in heavy-metal-based materials, such as, BaTe(111)-supported plumbene. Further investigations reveal that topologically nontrivial states can be realized by removing the Dirac band dispersion of the magnetic monolayers for the former case (such as in alkali metal doped CrBr3), while separating the two different spin channels from each other by enhancing the magnetic spin splitting for the latter case (such as in half-iodinated silicene). Thus, our work provides a theoretical guideline to manipulate the topological states in a two-dimensional honeycomb lattice.
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Affiliation(s)
- Yaling Zhang
- College of Chemistry and Materials Science, Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Shanxi Normal University, Taiyuan 030006, China.
| | - Jingjing Zhang
- College of Physics and Electronic Information, Shanxi Normal University, Taiyuan 030006, China
| | - Wenjia Yang
- College of Chemistry and Materials Science, Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Shanxi Normal University, Taiyuan 030006, China.
| | - Huisheng Zhang
- College of Chemistry and Materials Science, Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Shanxi Normal University, Taiyuan 030006, China.
- College of Physics and Electronic Information, Shanxi Normal University, Taiyuan 030006, China
| | - Jianfeng Jia
- College of Chemistry and Materials Science, Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Shanxi Normal University, Taiyuan 030006, China.
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8
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Zhong J, Yang M, Shi Z, Li Y, Mu D, Liu Y, Cheng N, Zhao W, Hao W, Wang J, Yang L, Zhuang J, Du Y. Towards layer-selective quantum spin hall channels in weak topological insulator Bi 4Br 2I 2. Nat Commun 2023; 14:4964. [PMID: 37587124 PMCID: PMC10432521 DOI: 10.1038/s41467-023-40735-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/01/2023] [Indexed: 08/18/2023] Open
Abstract
Weak topological insulators, constructed by stacking quantum spin Hall insulators with weak interlayer coupling, offer promising quantum electronic applications through topologically non-trivial edge channels. However, the currently available weak topological insulators are stacks of the same quantum spin Hall layer with translational symmetry in the out-of-plane direction-leading to the absence of the channel degree of freedom for edge states. Here, we study a candidate weak topological insulator, Bi4Br2I2, which is alternately stacked by three different quantum spin Hall insulators, each with tunable topologically non-trivial edge states. Our angle-resolved photoemission spectroscopy and first-principles calculations show that an energy gap opens at the crossing points of different Dirac cones correlated with different layers due to the interlayer interaction. This is essential to achieve the tunability of topological edge states as controlled by varying the chemical potential. Our work offers a perspective for the construction of tunable quantized conductance devices for future spintronic applications.
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Affiliation(s)
- Jingyuan Zhong
- School of Physics, Beihang University, Haidian District, Beijing, China
| | - Ming Yang
- School of Physics, Beihang University, Haidian District, Beijing, China
| | - Zhijian Shi
- School of Physics, Beihang University, Haidian District, Beijing, China
| | - Yaqi Li
- School of Physics, Beihang University, Haidian District, Beijing, China
| | - Dan Mu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan, China
| | - Yundan Liu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan, China
| | - Ningyan Cheng
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of Education, Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui, China
| | - Wenxuan Zhao
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China
| | - Weichang Hao
- School of Physics, Beihang University, Haidian District, Beijing, China
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, China
| | - Jianfeng Wang
- School of Physics, Beihang University, Haidian District, Beijing, China.
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China.
| | - Jincheng Zhuang
- School of Physics, Beihang University, Haidian District, Beijing, China.
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, China.
| | - Yi Du
- School of Physics, Beihang University, Haidian District, Beijing, China.
- Centre of Quantum and Matter Sciences, International Research Institute for Multidisciplinary Science, Beihang University, Beijing, China.
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9
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Lu Q, Li L, Luo S, Wang Y, Wang B, Liu FT. Oxygen functionalized InSe and TlTe two-dimensional materials: transition from tunable bandgap semiconductors to quantum spin Hall insulators. RSC Adv 2023; 13:18816-18824. [PMID: 37350867 PMCID: PMC10284147 DOI: 10.1039/d3ra02518g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Accepted: 06/14/2023] [Indexed: 06/24/2023] Open
Abstract
From first-principles calculations, we found that oxygen functionalized InSe and TlTe two-dimensional materials undergo the following changes with the increased concentrations of oxygen coverage, transforming from indirect bandgap semiconductors to direct bandgap semiconductors with tunable bandgap, and finally becoming quantum spin hall insulators. The maximal nontrivial bandgap are 0.121 and 0.169 eV, respectively, which occur at 100% oxygen coverage and are suitable for applications at room temperature. In addition, the topological phases are derived from SOC induced p-p bandgap opening, which can be further determined by Z2 topological invariants and topologically protected gapless edge states. Significantly, the topological phases can be maintained in excess of 75% oxygen coverage and are robust against external strain, making the quantum spin hall effect easy to achieve experimentally. Thus, the oxygen functionalized InSe and TlTe are fine candidate materials for the design and fabrication of topological devices.
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Affiliation(s)
- Qing Lu
- Key Laboratory of Computational Physics of Sichuan Province, Faculty of Science, Yibin University Yibin 644000 China
| | - Lin Li
- Key Laboratory of Computational Physics of Sichuan Province, Faculty of Science, Yibin University Yibin 644000 China
| | - Shilin Luo
- Key Laboratory of Computational Physics of Sichuan Province, Faculty of Science, Yibin University Yibin 644000 China
| | - Yue Wang
- Key Laboratory of Computational Physics of Sichuan Province, Faculty of Science, Yibin University Yibin 644000 China
| | - Busheng Wang
- Department of Chemistry, State University of New York at Buffalo Buffalo NY 14260-3000 USA
| | - Fu-Ti Liu
- Key Laboratory of Computational Physics of Sichuan Province, Faculty of Science, Yibin University Yibin 644000 China
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10
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Wu SL, Ren ZH, Zhang YQ, Li YK, Han JF, Duan JX, Wang ZW, Li CZ, Yao YG. Gate-tunable transport in van der Waals topological insulator Bi 4Br 4nanobelts. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:234001. [PMID: 36913735 DOI: 10.1088/1361-648x/acc3eb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/13/2023] [Indexed: 06/18/2023]
Abstract
Bi4Br4is a quasi-one-dimensional van der Waals topological insulator with novel electronic properties. Several efforts have been devoted to the understanding of its bulk form, yet it remains a challenge to explore the transport properties in low-dimensional structures due to the difficulty of device fabrication. Here we report for the first time a gate-tunable transport in exfoliated Bi4Br4nanobelts. Notable two-frequency Shubnikov-de Haas oscillations oscillations are discovered at low temperatures, with the low- and high-frequency parts coming from the three-dimensional bulk state and the two-dimensional surface state, respectively. In addition, ambipolar field effect is realized with a longitudinal resistance peak and a sign reverse in the Hall coefficient. Our successful measurements of quantum oscillations and realization of gate-tunable transport lay a foundation for further investigation of novel topological properties and room-temperature quantum spin Hall states in Bi4Br4.
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Affiliation(s)
- Si-Li Wu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Zhi-Hui Ren
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Yu-Qi Zhang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Yong-Kai Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314011, People's Republic of China
| | - Jun-Feng Han
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314011, People's Republic of China
| | - Jun-Xi Duan
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Zhi-Wei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Material Science Center, Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314011, People's Republic of China
| | - Cai-Zhen Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Yu-Gui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, People's Republic of China
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11
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Han J, Mao P, Chen H, Yin JX, Wang M, Chen D, Li Y, Zheng J, Zhang X, Ma D, Ma Q, Yu ZM, Zhou J, Liu CC, Wang Y, Jia S, Weng Y, Hasan MZ, Xiao W, Yao Y. Optical bulk-boundary dichotomy in a quantum spin Hall insulator. Sci Bull (Beijing) 2023:S2095-9273(23)00074-9. [PMID: 36740530 DOI: 10.1016/j.scib.2023.01.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 11/23/2022] [Accepted: 01/23/2023] [Indexed: 02/05/2023]
Abstract
The bulk-boundary correspondence is a critical concept in topological quantum materials. For instance, a quantum spin Hall insulator features a bulk insulating gap with gapless helical boundary states protected by the underlying Z2 topology. However, the bulk-boundary dichotomy and distinction are rarely explored in optical experiments, which can provide unique information about topological charge carriers beyond transport and electronic spectroscopy techniques. Here, we utilize mid-infrared absorption micro-spectroscopy and pump-probe micro-spectroscopy to elucidate the bulk-boundary optical responses of Bi4Br4, a recently discovered room-temperature quantum spin Hall insulator. Benefiting from the low energy of infrared photons and the high spatial resolution, we unambiguously resolve a strong absorption from the boundary states while the bulk absorption is suppressed by its insulating gap. Moreover, the boundary absorption exhibits strong polarization anisotropy, consistent with the one-dimensional nature of the topological boundary states. Our infrared pump-probe microscopy further measures a substantially increased carrier lifetime for the boundary states, which reaches one nanosecond scale. The nanosecond lifetime is about one to two orders longer than that of most topological materials and can be attributed to the linear dispersion nature of the helical boundary states. Our findings demonstrate the optical bulk-boundary dichotomy in a topological material and provide a proof-of-principal methodology for studying topological optoelectronics.
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Affiliation(s)
- Junfeng Han
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Pengcheng Mao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Analysis & Testing Center, Beijing Institute of Technology, Beijing 100081, China
| | - Hailong Chen
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton NJ 08544, USA
| | - Maoyuan Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Department of Physics, Xiamen University, Xiamen 361005, China
| | - Dongyun Chen
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Yongkai Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Jingchuan Zheng
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Xu Zhang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Dashuai Ma
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Department of Physics, Chongqing University, Chongqing 400044, China
| | - Qiong Ma
- Department of Physics, Boston College, Chestnut Hill MA 02467, USA
| | - Zhi-Ming Yu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Jinjian Zhou
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Cheng-Cheng Liu
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China
| | - Yeliang Wang
- School of Integrated Circuits and Electronics, MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, Beijing Institute of Technology, Beijing 100081, China
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Yuxiang Weng
- Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan 523808, China
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton NJ 08544, USA
| | - Wende Xiao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China.
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (Ministry of Education), School of Physics, Beijing Institute of Technology, Beijing 100081, China; Yangtze Delta Region Academy of Beijing Institute of Technology, Jiaxing 314000, China; Beijing Key Laboratory of Nanophotonics & Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing 100081, China.
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12
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Shumiya N, Hossain MS, Yin JX, Wang Z, Litskevich M, Yoon C, Li Y, Yang Y, Jiang YX, Cheng G, Lin YC, Zhang Q, Cheng ZJ, Cochran TA, Multer D, Yang XP, Casas B, Chang TR, Neupert T, Yuan Z, Jia S, Lin H, Yao N, Balicas L, Zhang F, Yao Y, Hasan MZ. Evidence of a room-temperature quantum spin Hall edge state in a higher-order topological insulator. NATURE MATERIALS 2022; 21:1111-1115. [PMID: 35835819 DOI: 10.1038/s41563-022-01304-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 05/29/2022] [Indexed: 06/15/2023]
Abstract
Room-temperature realization of macroscopic quantum phases is one of the major pursuits in fundamental physics1,2. The quantum spin Hall phase3-6 is a topological quantum phase that features a two-dimensional insulating bulk and a helical edge state. Here we use vector magnetic field and variable temperature based scanning tunnelling microscopy to provide micro-spectroscopic evidence for a room-temperature quantum spin Hall edge state on the surface of the higher-order topological insulator Bi4Br4. We find that the atomically resolved lattice exhibits a large insulating gap of over 200 meV, and an atomically sharp monolayer step edge hosts an in-gap gapless state, suggesting topological bulk-boundary correspondence. An external magnetic field can gap the edge state, consistent with the time-reversal symmetry protection inherent in the underlying band topology. We further identify the geometrical hybridization of such edge states, which not only supports the Z2 topology of the quantum spin Hall state but also visualizes the building blocks of the higher-order topological insulator phase. Our results further encourage the exploration of high-temperature transport quantization of the putative topological phase reported here.
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Affiliation(s)
- Nana Shumiya
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Md Shafayat Hossain
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
| | - Jia-Xin Yin
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
| | - Zhiwei Wang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Maksim Litskevich
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Chiho Yoon
- Department of Physics, University of Texas at Dallas, Richardson, TX, USA
- Department of Physics and Astronomy, Seoul National University, Seoul, Korea
| | - Yongkai Li
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Ying Yang
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - Yu-Xiao Jiang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Guangming Cheng
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA
| | - Yen-Chuan Lin
- Department of Physics, National Taiwan University, Taipei, Taiwan
| | - Qi Zhang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Zi-Jia Cheng
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Tyler A Cochran
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Daniel Multer
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Xian P Yang
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
| | - Brian Casas
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - Tay-Rong Chang
- Department of Physics, National Cheng Kung University, Tainan, Taiwan
- Center for Quantum Frontiers of Research and Technology (QFort), Tainan, Taiwan
- Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan
| | - Titus Neupert
- Department of Physics, University of Zürich, Zürich, Switzerland
| | - Zhujun Yuan
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China
- Beijing Academy of Quantum Information Sciences,, Beijing, China
| | - Shuang Jia
- International Center for Quantum Materials, School of Physics, Peking University, Beijing, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing, China
- Beijing Academy of Quantum Information Sciences,, Beijing, China
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Nan Yao
- Princeton Institute for Science and Technology of Materials, Princeton University, Princeton, NJ, USA
| | - Luis Balicas
- National High Magnetic Field Laboratory, Tallahassee, FL, USA
| | - Fan Zhang
- Department of Physics, University of Texas at Dallas, Richardson, TX, USA
| | - Yugui Yao
- Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, China
| | - M Zahid Hasan
- Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA.
- Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Quantum Science Center, Oak Ridge, TN, USA.
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13
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Jia X, Wang J, Lu Y, Sun J, Li Y, Wang Y, Zhang J. Designing SnS/MoS 2 van der Waals heterojunction for direct Z-scheme photocatalytic overall water-splitting by DFT investigation. Phys Chem Chem Phys 2022; 24:21321-21330. [PMID: 36043354 DOI: 10.1039/d2cp02692a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Construction of direct Z-scheme photocatalytic heterojunctions with an internal electric field has been proposed as an outstanding method to achieve efficient utilization of solar energy for photocatalytic overall water-splitting. In this work, the properties of van der Waals (vdW) heterojunctions formed by group-IV mono-chalcogenides (MXs) (M = Ge, Sn; X = S, Se, Te) and MoS2 are systematically studied by first-principles calculations, including the vdW binding energy, the direction of an internal electric field and the electronic structure. The results predict that GeS/MoS2, GeSe/MoS2 and SnS/MoS2 vdW heterojunctions are potential direct Z-scheme water-splitting photocatalysts with appropriate band alignments, a wide light absorption range and low effective charge-carrier mass. Furthermore, the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) activities of the heterojunctions as photocatalysts are predicted. The results indicate that SnS/MoS2 with the Sn vacancy has a low Gibbs free energy of the HER (0.06 eV), and MoS2 with the S edge can offer OER active sites. This study provides a theoretical basis for the further design and preparation of a new two-dimensional overall water-splitting photocatalyst, which is conducive to the development of efficient two-dimensional photocatalysts in the field of clean energy.
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Affiliation(s)
- Xiaofang Jia
- School of Physics, Beihang University, Beijing 100191, China.
| | - Jinlong Wang
- School of physics and Electronic Engineering, Xinxiang University, Xinxiang, 453003, China
| | - Yue Lu
- School of Physics, Beihang University, Beijing 100191, China.
| | - Jiaming Sun
- School of Physics, Beihang University, Beijing 100191, China.
| | - Yang Li
- School of Physics, Beihang University, Beijing 100191, China.
| | - Yuyan Wang
- Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China.
| | - Junying Zhang
- School of Physics, Beihang University, Beijing 100191, China.
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14
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Guo SD, Mu WQ, Guo HT, Tao YL, Liu BG. A piezoelectric quantum spin Hall insulator VCClBr monolayer with a pure out-of-plane piezoelectric response. Phys Chem Chem Phys 2022; 24:19965-19974. [PMID: 35971867 DOI: 10.1039/d2cp02724k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The combination of piezoelectricity with a nontrivial topological insulating phase in two-dimensional (2D) systems, namely piezoelectric quantum spin Hall insulators (PQSHI), is intriguing for exploring novel topological states toward the development of high-speed and dissipationless electronic devices. In this work, we predict a PQSHI Janus monolayer VCClBr constructed from VCCl2, which is dynamically, mechanically and thermally stable. In the absence of spin orbital coupling (SOC), VCClBr is a narrow gap semiconductor with a gap value of 57 meV, which is different from Dirac semimetal VCCl2. The gap of VCClBr is due to a built-in electric field caused by asymmetrical upper and lower atomic layers, which is further confirmed by the external-electric-field induced gap in VCCl2. When including SOC, the gap of VCClBr is increased to 76 meV, which is larger than the thermal energy of room temperature (25 meV). The VCClBr is a 2D topological insulator (TI), which is confirmed by Z2 topological invariant and nontrivial one-dimensional edge states. It is proved that the nontrivial topological properties of VCClBr are robust against strain (biaxial and uniaxial cases) and external electric fields. Due to broken horizontal mirror symmetry, only an out-of-plane piezoelectric response can be observed, when a biaxial or uniaxial in-plane strain is applied. The predicted piezoelectric strain coefficients d31 and d32 are -0.425 pm V-1 and -0.219 pm V-1, respectively, and they are higher than or compared with those of many 2D materials. Finally, Janus monolayer VCFBr and VCFCl (dynamically unstable) are also constructed, and they are still PQSHIs. Moreover, the d31 and d32 of VCFBr and VCFCl are higher than those of VCClBr, and the d31 (absolute value) of VCFBr is larger than one. According to out-of-plane piezoelectric coefficients of VCXY (X ≠ Y = F, Cl and Br), CrX1.5Y1.5 (X = F, Cl and Br; Y = I) and NiXY (X ≠ Y = Cl, Br and I), it is concluded that the size of the out-of-plane piezoelectric coefficient has a positive relation with the electronegativity difference of X and Y atoms. Our studies enrich the diversity of Janus 2D materials, and open a new avenue in the search for PQSHI with a large out-of-plane piezoelectric response, which provides a potential platform in nanoelectronics.
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Affiliation(s)
- San-Dong Guo
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, P. R. China.
| | - Wen-Qi Mu
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, P. R. China.
| | - Hao-Tian Guo
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, P. R. China.
| | - Yu-Ling Tao
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, P. R. China.
| | - Bang-Gui Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, P. R. China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, P. R. China
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15
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Guo SD, Zhu YT. Spin-valley-coupled quantum spin Hall insulator with topological Rashba-splitting edge states in Janus monolayer CSb 1.5Bi 1.5. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:235501. [PMID: 35134787 DOI: 10.1088/1361-648x/ac5313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 02/08/2022] [Indexed: 06/14/2023]
Abstract
Achieving combination of spin and valley polarized states with topological insulating phase is pregnant to promote the fantastic integration of topological physics, spintronics and valleytronics. In this work, a spin-valley-coupled quantum spin Hall insulator (svc-QSHI) is predicted in Janus monolayer CSb1.5Bi1.5with dynamic, mechanical and thermal stabilities. Calculated results show that the CSb1.5Bi1.5is a direct band gap semiconductor with and without spin-orbit coupling, and the conduction-band minimum and valence-band maximum are at valley point. The inequivalent valleys have opposite Berry curvature and spin moment, which can produce a spin-valley Hall effect. In the center of Brillouin zone, a Rashba-type spin splitting can be observed due to missing horizontal mirror symmetry. The topological characteristic of CSb1.5Bi1.5is confirmed by theZ2invariant and topological protected conducting helical edge states. Moreover, the CSb1.5Bi1.5shows unique Rashba-splitting edge states. Both energy band gap and spin-splitting at the valley point are larger than the thermal energy of room temperature (25 meV) with generalized gradient approximation level, which is very important at room temperature for device applications. It is proved that the spin-valley-coupling and nontrivial quantum spin Hall state are robust again biaxial strain. Our work may provide a new platform to achieve integration of topological physics, spintronics and valleytronics.
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Affiliation(s)
- San-Dong Guo
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, People's Republic of China
| | - Yu-Tong Zhu
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, People's Republic of China
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16
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Yang M, Liu Y, Zhou W, Liu C, Mu D, Liu Y, Wang J, Hao W, Li J, Zhong J, Du Y, Zhuang J. Large-Gap Quantum Spin Hall State and Temperature-Induced Lifshitz Transition in Bi 4Br 4. ACS NANO 2022; 16:3036-3044. [PMID: 35049268 DOI: 10.1021/acsnano.1c10539] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Searching for quantum spin Hall insulators with large fully opened energy gap to overcome the thermal disturbance at room temperature has attracted tremendous attention because of the robustness of one-dimensional (1D) spin-momentum locked topological edge states in the practical applications of electronic devices and spintronics. Here, we report the investigation of topological nature of monolayer Bi4Br4 by the techniques of angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy. The possible topological nontriviality of 1D edge state integrals within the large energy gap (∼0.2 eV) is revealed by the first-principle calculations. The ARPES measurements at different temperatures show a temperature-induced Lifshitz transition, corresponding to the resistivity anomaly evoked by the chemical potential shift. The connection between the emergency of superconductivity and the Lifshitz transition is discussed.
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Affiliation(s)
- Ming Yang
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Yundan Liu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Wei Zhou
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu, 215500, China
| | - Chen Liu
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Dan Mu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yani Liu
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
| | - Jiaou Wang
- Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Weichang Hao
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Jin Li
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Jianxin Zhong
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yi Du
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
| | - Jincheng Zhuang
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
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17
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Liu Y, Chen R, Zhang Z, Bockrath M, Lau CN, Zhou YF, Yoon C, Li S, Liu X, Dhale N, Lv B, Zhang F, Watanabe K, Taniguchi T, Huang J, Yi M, Oh JS, Birgeneau RJ. Gate-Tunable Transport in Quasi-One-Dimensional α-Bi 4I 4 Field Effect Transistors. NANO LETTERS 2022; 22:1151-1158. [PMID: 35077182 DOI: 10.1021/acs.nanolett.1c04264] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Bi4I4 belongs to a novel family of quasi-one-dimensional (1D) topological insulators (TIs). While its β phase was demonstrated to be a prototypical weak TI, the α phase, long thought to be a trivial insulator, was recently predicted to be a rare higher order TI. Here, we report the first gate tunable transport together with evidence for unconventional band topology in exfoliated α-Bi4I4 field effect transistors. We observe a Dirac-like longitudinal resistance peak and a sign change in the Hall resistance; their temperature dependences suggest competing transport mechanisms: a hole-doped insulating bulk and one or more gate-tunable ambipolar boundary channels. Our combined transport, photoemission, and theoretical results indicate that the gate-tunable channels likely arise from novel gapped side surface states, two-dimensional (2D) TI in the bottommost layer, and/or helical hinge states of the upper layers. Markedly, a gate-tunable supercurrent is observed in an α-Bi4I4 Josephson junction, underscoring the potential of these boundary channels to mediate topological superconductivity.
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Affiliation(s)
- Yulu Liu
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Ruoyu Chen
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Zheneng Zhang
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Marc Bockrath
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Chun Ning Lau
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, United States
| | - Yan-Feng Zhou
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Chiho Yoon
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
| | - Sheng Li
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Xiaoyuan Liu
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Nikhil Dhale
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Bing Lv
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Fan Zhang
- Department of Physics, The University of Texas at Dallas, 800 West Campbell Road, Richardson, Texas 75080-3021, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Jianwei Huang
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Ming Yi
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, United States
| | - Ji Seop Oh
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, United States
| | - Robert J Birgeneau
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, United States
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18
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Sharan A, Singh N. Intrinsic Valley Polarization in Computationally Discovered Two‐Dimensional Ferrovalley Materials: LaI
2
and PrI
2
Monolayers. ADVANCED THEORY AND SIMULATIONS 2022. [DOI: 10.1002/adts.202100476] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Abhishek Sharan
- Department of Physics Khalifa University of Science and Technology Abu Dhabi 127788 UAE
| | - Nirpendra Singh
- Department of Physics Khalifa University of Science and Technology Abu Dhabi 127788 UAE
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19
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Guo SD, Mu WQ, Xiao XB, Liu BG. Generalization of piezoelectric quantum anomalous Hall insulator based on monolayer Fe 2I 2: a first-principles study. Phys Chem Chem Phys 2021; 23:25994-26003. [PMID: 34783808 DOI: 10.1039/d1cp04123a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To easily synthesize a piezoelectric quantum anomalous Hall insulator (PQAHI), the Janus monolayer Fe2IBr (FeI0.5Br0.5) as a representative PQAHI, is generalized to monolayer FeI1-xBrx (x = 0.25 and 0.75) with α and β phases. By first-principles calculations, it is proved that monolayer FeI1-xBrx (x = 0.25 and 0.75) are dynamically, mechanically and thermally stable. They are excellent room-temperature PQAHIs with high Curie temperatures, sizable gaps and high Chern number (C = 2). Because the considered crystal structures of α and β phases possess Mx and My mirror symmetries, the topological properties of monolayer FeI1-xBrx (x = 0.25 and 0.75) are maintained. Namely, if the constructed structures have Mx and My mirror symmetries, the mixing ratio of Br and I atoms can be generalized for other proportions. It is also found that different crystal phases have important effects on the out-of-plane piezoelectric response, and the piezoelectric strain coefficient, d32, of the β phase is higher than or comparable with those of other known two-dimensional (2D) materials. To further confirm this idea, the physical and chemical properties of monolayer LiFeSe0.75S0.25 with α and β phases, as a generalization of PQAHI LiFeSe0.5S0.5, is investigated, as it has a similar electronic structure, magnetic and topological properties as LiFeSe0.5S0.5. Our work provides a practical guide to achieve PQAHIs experimentally, and the combination of piezoelectricity, topological and ferromagnetic (FM) orders makes Fe2I2-based monolayers a potential platform for multi-functional spintronics and piezoelectric electronics.
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Affiliation(s)
- San-Dong Guo
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, People's Republic of China.
| | - Wen-Qi Mu
- School of Electronic Engineering, Xi'an University of Posts and Telecommunications, Xi'an 710121, People's Republic of China.
| | - Xiang-Bo Xiao
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
| | - Bang-Gui Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China.,School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190, People's Republic of China
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20
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Peng X, Zhang X, Dong X, Ma D, Chen D, Li Y, Li J, Han J, Wang Z, Liu CC, Zhou J, Xiao W, Yao Y. Observation of Topological Edge States on α-Bi 4Br 4 Nanowires Grown on TiSe 2 Substrates. J Phys Chem Lett 2021; 12:10465-10471. [PMID: 34672593 DOI: 10.1021/acs.jpclett.1c02586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A time-reversal invariant two-dimensional (2D) topological insulator (TI) is characterized by the gapless helical edge states propagating along the perimeter of the system. However, the small band gap in the 2D TIs discovered so far hinders their applications. Recently, we predicted that single-layer Bi4Br4 is a 2D TI with a remarkable band gap and that α-Bi4Br4 crystals can host topological edge states at the step edges. Here we report the growth of α-Bi4Br4 nanowires with (102)-oriented top surfaces on the TiSe2 substrates and the direct observation of the predicted topological edge states at the step edges of the nanowires using scanning tunneling microscopy. The coupling between the edge states leads to the formation of surface states at the (102) top surfaces of the nanowires. Our work demonstrates the existence of topological edge states in α-Bi4Br4 and paves the way for developing α-Bi4Br4-based devices for a high-temperature quantum spin Hall effect.
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Affiliation(s)
- Xianglin Peng
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Xu Zhang
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Xu Dong
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Dashuai Ma
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Dongyun Chen
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Yongkai Li
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Ji Li
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
| | - Junfeng Han
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, China
| | - Zhiwei Wang
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, China
| | - Cheng-Cheng Liu
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, China
| | - Jinjian Zhou
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, China
| | - Wende Xiao
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, China
| | - Yugui Yao
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education, School of Physics, Beijing Institute of Technology, Beijing, 100081, China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic Systems, Beijing Institute of Technology, Beijing, 100081, China
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21
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Zhuang J, Li J, Liu Y, Mu D, Yang M, Liu Y, Zhou W, Hao W, Zhong J, Du Y. Epitaxial Growth of Quasi-One-Dimensional Bismuth-Halide Chains with Atomically Sharp Topological Non-Trivial Edge States. ACS NANO 2021; 15:14850-14857. [PMID: 34583466 DOI: 10.1021/acsnano.1c04928] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Quantum spin Hall insulators (QSHIs) have one-dimensional (1D) spin-momentum locked topological edge states (ES) inside the bulk band gap, which can serve as dissipationless channels for the practical applications in low consumption electronics and high performance spintronics. However, obtaining the clean and atomically sharp ES which serves as ideal 1D spin-polarized nondissipative conducting channels is demanding and still a challenge. Here, we report the formation of the quasi-1D Bi4I4 nanoribbons on the surface of Bi(111) with the support of the graphene-terminated 6H-SiC(0001) and the direct observation of the topological ES at the step edges by the scanning tunneling microscopy (STM) and spectroscopic-imaging results. The ES reside surround the edge of Bi4I4 nanoribbons and exhibits noteworthy robustness against nontime reversal symmetry (non-TRS) perturbations. The theoretical simulations verify the topological nontriviality of 1D ES, which is retained after considering the presence of the underlying Bi(111). Our study supports the existence of topological ES in Bi4I4 nanoribbons, benefiting to engineer the topological features by using the 1D nanoribbons as building blocks.
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Affiliation(s)
- Jincheng Zhuang
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Jin Li
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yundan Liu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Dan Mu
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Ming Yang
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Yani Liu
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
| | - Wei Zhou
- School of Electronic and Information Engineering, Changshu Institute of Technology, Changshu 215500, China
| | - Weichang Hao
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
| | - Jianxin Zhong
- Hunan Key Laboratory of Micro-Nano Energy Materials and Devices, and School of Physics and Optoelectronics, Xiangtan University, Hunan 411105, China
| | - Yi Du
- School of Physics and BUAA-UOW Joint Research Centre, Beihang University, Haidian District, Beijing 100191, China
- Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials, University of Wollongong, Wollongong, New South Wales 2500, Australia
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22
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Zhang H, Wang Y, Yang W, Zhang J, Xu X, Liu F. Selective Substrate-Orbital-Filtering Effect to Realize the Large-Gap Quantum Spin Hall Effect. NANO LETTERS 2021; 21:5828-5833. [PMID: 34156241 DOI: 10.1021/acs.nanolett.1c01765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Although Pb harbors a strong spin-orbit coupling effect, pristine plumbene (the last group-IV cousin of graphene) hosts topologically trivial states. Based on first-principles calculations, we demonstrate that epitaxial growth of plumbene on the BaTe(111) surface converts the trivial Pb lattice into a quantum spin Hall (QSH) phase with a large gap of ∼0.3 eV via a selective substrate-orbital-filtering effect. Tight-binding model analyses show the pz orbital in half of the Pb overlayer is selectively removed by the BaTe substrate, leaving behind a pz-px,y band inversion. Based on the same working principle, the gap can be further increased to ∼0.5-0.6 eV by surface adsorption of H or halogen atoms that filters out the other half of the Pb pz orbitals. The mechanism of selective substrate-orbital-filtering is general, opening an avenue to explore large-gap QSH insulators in heavy-metal-based materials. It is worth noting that plumbene has already been widely grown on various substrates experimentally.
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Affiliation(s)
- Huisheng Zhang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and Research Institute of Materials Science, Shanxi Normal University, Linfen 041004, China
| | - Yingying Wang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and Research Institute of Materials Science, Shanxi Normal University, Linfen 041004, China
| | - Wenjia Yang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and Research Institute of Materials Science, Shanxi Normal University, Linfen 041004, China
| | - Jingjing Zhang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and Research Institute of Materials Science, Shanxi Normal University, Linfen 041004, China
| | - Xiaohong Xu
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education and Research Institute of Materials Science, Shanxi Normal University, Linfen 041004, China
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112, United States
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23
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Noguchi R, Kobayashi M, Jiang Z, Kuroda K, Takahashi T, Xu Z, Lee D, Hirayama M, Ochi M, Shirasawa T, Zhang P, Lin C, Bareille C, Sakuragi S, Tanaka H, Kunisada S, Kurokawa K, Yaji K, Harasawa A, Kandyba V, Giampietri A, Barinov A, Kim TK, Cacho C, Hashimoto M, Lu D, Shin S, Arita R, Lai K, Sasagawa T, Kondo T. Evidence for a higher-order topological insulator in a three-dimensional material built from van der Waals stacking of bismuth-halide chains. NATURE MATERIALS 2021; 20:473-479. [PMID: 33398124 DOI: 10.1038/s41563-020-00871-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 11/09/2020] [Indexed: 06/12/2023]
Abstract
Low-dimensional van der Waals materials have been extensively studied as a platform with which to generate quantum effects. Advancing this research, topological quantum materials with van der Waals structures are currently receiving a great deal of attention. Here, we use the concept of designing topological materials by the van der Waals stacking of quantum spin Hall insulators. Most interestingly, we find that a slight shift of inversion centre in the unit cell caused by a modification of stacking induces a transition from a trivial insulator to a higher-order topological insulator. Based on this, we present angle-resolved photoemission spectroscopy results showing that the real three-dimensional material Bi4Br4 is a higher-order topological insulator. Our demonstration that various topological states can be selected by stacking chains differently, combined with the advantages of van der Waals materials, offers a playground for engineering topologically non-trivial edge states towards future spintronics applications.
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Affiliation(s)
- Ryo Noguchi
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Masaru Kobayashi
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan
| | - Zhanzhi Jiang
- Department of Physics, University of Texas at Austin, Austin, TX, United States
| | - Kenta Kuroda
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Takanari Takahashi
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan
| | - Zifan Xu
- Department of Physics, University of Texas at Austin, Austin, TX, United States
| | - Daehun Lee
- Department of Physics, University of Texas at Austin, Austin, TX, United States
| | | | - Masayuki Ochi
- Department of Physics, Osaka University, Toyonaka, Japan
| | - Tetsuroh Shirasawa
- National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Peng Zhang
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Chun Lin
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Cédric Bareille
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Shunsuke Sakuragi
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Hiroaki Tanaka
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - So Kunisada
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Kifu Kurokawa
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Koichiro Yaji
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | - Ayumi Harasawa
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
| | | | | | | | - Timur K Kim
- Diamond Light Source, Didcot, United Kingdom
| | | | - Makoto Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Donghui Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, USA
| | - Shik Shin
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan
- Office of University Professor, The University of Tokyo, Kashiwa, Japan
| | - Ryotaro Arita
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, Japan
| | - Keji Lai
- Department of Physics, University of Texas at Austin, Austin, TX, United States
| | - Takao Sasagawa
- Materials and Structures Laboratory, Tokyo Institute of Technology, Yokohama, Japan.
| | - Takeshi Kondo
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Japan.
- Trans-scale Quantum Science Institute, The University of Tokyo, Tokyo, Japan.
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24
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Yang S, Liu X, Lu S, Li Z, Zhang Y, Yu S, Song J, Ding C, Yang H. Novel Facile One‐Pot Synthesis of Bi
2
S
3
−BiOCl Ultrathin Hetero‐nanosheets for Selective Alcohol Oxidation. ChemCatChem 2021. [DOI: 10.1002/cctc.202100011] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Shouning Yang
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis Institute of Mass Spectrometry School of Material Science and Chemical Engineering Ningbo University Ningbo Zhejiang 315211 P.R. China
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education School of Chemistry and Chemical Engineering Henan Normal University Xinxiang Henan 453007 P.R. China
| | - Xiaoyang Liu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education School of Chemistry and Chemical Engineering Henan Normal University Xinxiang Henan 453007 P.R. China
| | - Sijia Lu
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education School of Chemistry and Chemical Engineering Henan Normal University Xinxiang Henan 453007 P.R. China
| | - Zhuo Li
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education School of Chemistry and Chemical Engineering Henan Normal University Xinxiang Henan 453007 P.R. China
| | - Yanmin Zhang
- School of Physics Henan Normal University Xinxiang Henan 453007 P.R. China
| | - Shaoning Yu
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis Institute of Mass Spectrometry School of Material Science and Chemical Engineering Ningbo University Ningbo Zhejiang 315211 P.R. China
| | - Jian Song
- School of Physics Henan Normal University Xinxiang Henan 453007 P.R. China
| | - Chuanfan Ding
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis Institute of Mass Spectrometry School of Material Science and Chemical Engineering Ningbo University Ningbo Zhejiang 315211 P.R. China
| | - Huayan Yang
- Zhejiang Provincial Key Laboratory of Advanced Mass Spectrometry and Molecular Analysis Institute of Mass Spectrometry School of Material Science and Chemical Engineering Ningbo University Ningbo Zhejiang 315211 P.R. China
- Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals Key Laboratory of Green Chemical Media and Reactions Ministry of Education School of Chemistry and Chemical Engineering Henan Normal University Xinxiang Henan 453007 P.R. China
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25
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Shi L, Li Q. Families of asymmetrically functionalized germanene films as promising quantum spin Hall insulators. Phys Chem Chem Phys 2021; 23:3595-3605. [PMID: 33523064 DOI: 10.1039/d0cp06231f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Topological insulators (TIs), exhibiting the quantum spin Hall (QSH) effect, are promising for developing dissipationless transport devices that can be realized under a wide range of temperatures. The search for new two-dimensional (2D) TIs is essential for TIs to be utilized at room-temperature, with applications in optoelectronics, spintronics, and magnetic sensors. In this work, we used first-principles calculations to investigate the geometric, electronic, and topological properties of GeX and GeMX (M = C, N, P, As; X = H, F, Cl, Br, I, O, S, Se, Te). In 26 of these materials, the QSH effect is demonstrated by a spin-orbit coupling (SOC) induced large band gap and a band inversion at the Γ point, similar to the case of an HgTe quantum well. In addition, engineering the intra-layer strain of certain GeMX species can transform them from a regular insulator into a 2D TI. This work demonstrates that asymmetrical chemical functionalization is a promising method to induce the QSH effect in 2D hexagonal materials, paving the way for practical application of TIs in electronics.
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Affiliation(s)
- Lawrence Shi
- Department of Electrical and Computer Engineering, George Mason University, Fairfax, Virginia 22030, USA.
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26
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Pabst F, Chang J, Finzel K, Kohout M, Schmidt P, Ruck M. The Subbromide Bi
5
Br
4
– On the Existence of a Hidden Phase. Z Anorg Allg Chem 2019. [DOI: 10.1002/zaac.201800149] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Falk Pabst
- Faculty of Chemistry and Food Chemistry Technische Universität Dresden 01062 Dresden Germany
| | - Jen‐Hui Chang
- Faculty of Chemistry and Food Chemistry Technische Universität Dresden 01062 Dresden Germany
| | - Kati Finzel
- Faculty of Chemistry and Food Chemistry Technische Universität Dresden 01062 Dresden Germany
| | - Miroslav Kohout
- Max Planck Institute for Chemical Physics of Solids Nöthnitzer Str. 40 01187 Dresden Germany
| | - Peer Schmidt
- Brandenburgische Technische Universität Cottbus Senftenberg Universitätsplatz 1 01968 Senftenberg Germany
| | - Michael Ruck
- Faculty of Chemistry and Food Chemistry Technische Universität Dresden 01062 Dresden Germany
- Max Planck Institute for Chemical Physics of Solids Nöthnitzer Str. 40 01187 Dresden Germany
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27
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Pressure-induced phase transitions and superconductivity in a quasi-1-dimensional topological crystalline insulator α-Bi 4Br 4. Proc Natl Acad Sci U S A 2019; 116:17696-17700. [PMID: 31420513 DOI: 10.1073/pnas.1909276116] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Great progress has been achieved in the research field of topological states of matter during the past decade. Recently, a quasi-1-dimensional bismuth bromide, Bi4Br4, has been predicted to be a rotational symmetry-protected topological crystalline insulator; it would also exhibit more exotic topological properties under pressure. Here, we report a thorough study of phase transitions and superconductivity in a quasihydrostatically pressurized α-Bi4Br4 crystal by performing detailed measurements of electrical resistance, alternating current magnetic susceptibility, and in situ high-pressure single-crystal X-ray diffraction together with first principles calculations. We find a pressure-induced insulator-metal transition between ∼3.0 and 3.8 GPa where valence and conduction bands cross the Fermi level to form a set of small pockets of holes and electrons. With further increase of pressure, 2 superconductive transitions emerge. One shows a sharp resistance drop to 0 near 6.8 K at 3.8 GPa; the transition temperature gradually lowers with increasing pressure and completely vanishes above 12.0 GPa. Another transition sets in around 9.0 K at 5.5 GPa and persists up to the highest pressure of 45.0 GPa studied in this work. Intriguingly, we find that the first superconducting phase might coexist with a nontrivial rotational symmetry-protected topology in the pressure range of ∼3.8 to 4.3 GPa; the second one is associated with a structural phase transition from monoclinic C2/m to triclinic P-1 symmetry.
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Zhang H, Ning Y, Yang W, Zhang R, Xu X. Topological phase transition induced by p x,y and p z band inversion in a honeycomb lattice. NANOSCALE 2019; 11:13807-13814. [PMID: 31294742 DOI: 10.1039/c9nr04268g] [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
The search for more types of band inversion-induced topological states is of great scientific and experimental interest. Here, we proposed that the band inversion between px,y and pz orbitals can produce a topological phase transition in honeycomb lattices based on tight-binding model analyses. The corresponding topological phase diagram was mapped out in the parameter space of orbital energy and spin-orbit coupling. Specifically, the quantum anomalous Hall (QAH) effect could be achieved when ferromagnetism was introduced. Moreover, our first-principles calculations demonstrated that the two systems of half-iodinated silicene (Si2I) and one-third monolayer of bismuth epitaxially grown on the Si(111)-√3 ×√3 surface are ideal candidates for realizing the QAH effect with Curie temperatures of ∼101 K and 118 K, respectively. The underlying physical mechanism of this scheme is generally applicable, offering broader opportunities for the exploration of novel topological states and high-temperature QAH effect systems.
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Affiliation(s)
- Huisheng Zhang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, and College of Physics and Electronic Information, Shanxi Normal University, Linfen 041004, China. and State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China
| | - Yaohui Ning
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, and College of Physics and Electronic Information, Shanxi Normal University, Linfen 041004, China.
| | - Wenjia Yang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, and College of Physics and Electronic Information, Shanxi Normal University, Linfen 041004, China.
| | - Ruiqiang Zhang
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, and College of Physics and Electronic Information, Shanxi Normal University, Linfen 041004, China.
| | - Xiaohong Xu
- Key Laboratory of Magnetic Molecules and Magnetic Information Materials of the Ministry of Education, Research Institute of Materials Science, and College of Physics and Electronic Information, Shanxi Normal University, Linfen 041004, China.
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Lu Q, Wen YM, Zeng ZY, Chen XR, Chen QF. Oxygen-functionalized TlTe buckled honeycomb from first-principles study. Phys Chem Chem Phys 2019; 21:5689-5694. [PMID: 30801076 DOI: 10.1039/c8cp07246a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A sizable band gap is crucial for the applications of topological insulators at room temperature. By first-principles calculations, we found that oxygen-functionalized TlTe buckled honeycomb, namely TlTeO, possessed quantum spin Hall (QSH) state with a sizable band gap of 0.17 eV, which owns potential applications at the room temperature. The QSH phase of TlTeO arose from the SOC-induced p-p band gap opening. In addition, the QSH phase was further confirmed by the topological invariant Z2 and gapless edge state in the bulk gap. Significantly, the QSH phase is robustly against the external strain and possesses more than 75% oxygen coverage, making the QSH effect of TlTeO easy to be achieved experimentally. Thus, the oxygen-functionalized TlTeO film is a fine candidate material for the topological device design and fabrication.
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Affiliation(s)
- Qing Lu
- Institute of Atomic and Molecular Physics, College of Physical Science and Technology, Sichuan University, Chengdu 610064, China.
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Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet. Sci Rep 2018; 8:7436. [PMID: 29743631 PMCID: PMC5943254 DOI: 10.1038/s41598-018-25478-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/23/2018] [Indexed: 11/08/2022] Open
Abstract
Spin-valley and electronic band topological properties have been extensively explored in quantum material science, yet their coexistence has rarely been realized in stoichiometric two-dimensional (2D) materials. We theoretically predict the quantum spin Hall effect (QSHE) in the hydrofluorinated bismuth (Bi2HF) nanosheet where the hydrogen (H) and fluorine (F) atoms are functionalized on opposite sides of bismuth (Bi) atomic monolayer. Such Bi2HF nanosheet is found to be a 2D topological insulator with a giant band gap of 0.97 eV which might host room temperature QSHE. The atomistic structure of Bi2HF nanosheet is noncentrosymmetric and the spontaneous polarization arises from the hydrofluorinated morphology. The phonon spectrum and ab initio molecular dynamic (AIMD) calculations reveal that the proposed Bi2HF nanosheet is dynamically and thermally stable. The inversion symmetry breaking together with spin-orbit coupling (SOC) leads to the coupling between spin and valley in Bi2HF nanosheet. The emerging valley-dependent properties and the interplay between intrinsic dipole and SOC are investigated using first-principles calculations combined with an effective Hamiltonian model. The topological invariant of the Bi2HF nanosheet is confirmed by using Wilson loop method and the calculated helical metallic edge states are shown to host QSHE. The Bi2HF nanosheet is therefore a promising platform to realize room temperature QSHE and valley spintronics.
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Wu S, Fatemi V, Gibson QD, Watanabe K, Taniguchi T, Cava RJ, Jarillo-Herrero P. Observation of the quantum spin Hall effect up to 100 kelvin in a monolayer crystal. Science 2018; 359:76-79. [PMID: 29302010 DOI: 10.1126/science.aan6003] [Citation(s) in RCA: 237] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 11/17/2017] [Indexed: 12/14/2022]
Abstract
A variety of monolayer crystals have been proposed to be two-dimensional topological insulators exhibiting the quantum spin Hall effect (QSHE), possibly even at high temperatures. Here we report the observation of the QSHE in monolayer tungsten ditelluride (WTe2) at temperatures up to 100 kelvin. In the short-edge limit, the monolayer exhibits the hallmark transport conductance, ~e2/h per edge, where e is the electron charge and h is Planck's constant. Moreover, a magnetic field suppresses the conductance, and the observed Zeeman-type gap indicates the existence of a Kramers degenerate point and the importance of time-reversal symmetry for protection from elastic backscattering. Our results establish the QSHE at temperatures much higher than in semiconductor heterostructures and allow for exploring topological phases in atomically thin crystals.
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Affiliation(s)
- Sanfeng Wu
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
| | - Valla Fatemi
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA.
| | - Quinn D Gibson
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Kenji Watanabe
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Robert J Cava
- Department of Chemistry, Princeton University, Princeton, NJ 08544, USA
| | - Pablo Jarillo-Herrero
- Department of Physics, Massachusetts Institute of Technology (MIT), Cambridge, MA 02139, USA
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Wang YP, Li SS, Ji WX, Zhang CW, Li P, Wang PJ. Bismuth oxide film: a promising room-temperature quantum spin Hall insulator. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:105303. [PMID: 29381144 DOI: 10.1088/1361-648x/aaabaa] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two-dimensional (2D) bismuth films have attracted extensive attention due to their nontrivial band topology and tunable electronic properties for achieving dissipationless transport devices. The experimental observation of quantum transport properties, however, are rather challenging, limiting their potential application in nanodevices. Here, we predict, based on first-principles calculations, an alternative 2D bismuth oxide, BiO, as an excellent topological insulator (TI), whose intrinsic bulk gap reaches up to 0.28 eV. Its nontrivial topology is confirmed by topological invariant Z 2 and time-reversal symmetry protected helical edge states. The appearance of topological phase is robust against mechanical strain and different levels of oxygen coverage in BiO. Since the BiO is naturally stable against surface oxidization and degradation, these results enrich the topological materials and present an alternative way to design topotronics devices at room temperature.
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Affiliation(s)
- Ya-Ping Wang
- School of Physics and Technology, University of Jinan, Jinan, Shandong 250022, People's Republic of China. Advanced Materials Institute, Shandong Key Laboratory for High Strength Lightweight Metallic Materials, Qilu University of Technology (Shandong Academy of Science), Jinan, Shandong 250014, People's Republic of China
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Teshome T, Datta A. Topological Insulator in Two-Dimensional SiGe Induced by Biaxial Tensile Strain. ACS OMEGA 2018; 3:1-7. [PMID: 31457874 PMCID: PMC6641324 DOI: 10.1021/acsomega.7b01957] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 12/19/2017] [Indexed: 06/10/2023]
Abstract
Strain-engineered two-dimensional (2D) SiGe is predicted to be a topological insulator (TI) based on first-principle calculations. The dynamical and thermal stabilities were ascertained through phonon spectra and ab initio molecular dynamics simulations. 2D SiGe remains dynamically stable under tensile strains of 4 and 6%. A band inversion was observed at the Γ-point with a band gap of 25 meV for 6% strain due to spin-orbit coupling interactions. Nontrivial of the TI phase was determined by its topological invariant (υ = 1). For SiGe nanoribbon with edge states, the valence band and conduction band cross at the Γ-point to create a topologically protected Dirac cone inside the bulk gap. We found that hexagonal boron nitride (h-BN) with high dielectric constant and band gap can be a very stable support to experimentally fabricate 2D SiGe as the h-BN layer does not alter its nontrivial topological character. Unlike other heavy-metal-based 2D systems, because SiGe has a sufficiently large gap, it can be utilized for spintronics and quantum spin Hall-based applications under ambient condition.
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Zhang S, Guo S, Chen Z, Wang Y, Gao H, Gómez-Herrero J, Ares P, Zamora F, Zhu Z, Zeng H. Recent progress in 2D group-VA semiconductors: from theory to experiment. Chem Soc Rev 2018; 47:982-1021. [DOI: 10.1039/c7cs00125h] [Citation(s) in RCA: 595] [Impact Index Per Article: 99.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review provides recent theoretical and experimental progress in the fundamental properties, electronic modulations, fabrications and applications of 2D group-VA materials.
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Affiliation(s)
- Shengli Zhang
- MIIT Key Laboratory of Advanced Display Materials and Devices
- Ministry of Industry and Information Technology
- Institute of Optoelectronics & Nanomaterials
- Nanjing University of Science and Technology
- Nanjing
| | - Shiying Guo
- MIIT Key Laboratory of Advanced Display Materials and Devices
- Ministry of Industry and Information Technology
- Institute of Optoelectronics & Nanomaterials
- Nanjing University of Science and Technology
- Nanjing
| | - Zhongfang Chen
- Department of Chemistry
- Institute for Functional Nanomaterials
- University of Puerto Rico
- San Juan
- USA
| | - Yeliang Wang
- Institute of Physics and University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Hongjun Gao
- Institute of Physics and University of Chinese Academy of Sciences
- Chinese Academy of Sciences
- Beijing 100190
- China
| | - Julio Gómez-Herrero
- Departamento de Física de la Materia Condensada
- Universidad Autónoma de Madrid
- Madrid E 28049
- Spain
| | - Pablo Ares
- Departamento de Física de la Materia Condensada
- Universidad Autónoma de Madrid
- Madrid E 28049
- Spain
| | - Félix Zamora
- Departamento de Química Inorgánica
- Universidad Autónoma de Madrid
- Madrid E 28049
- Spain
| | - Zhen Zhu
- Materials Department
- University of California
- Santa Barbara
- USA
| | - Haibo Zeng
- MIIT Key Laboratory of Advanced Display Materials and Devices
- Ministry of Industry and Information Technology
- Institute of Optoelectronics & Nanomaterials
- Nanjing University of Science and Technology
- Nanjing
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Du J, Xia C, Xiong W, Wang T, Jia Y, Li J. Two-dimensional transition-metal dichalcogenides-based ferromagnetic van der Waals heterostructures. NANOSCALE 2017; 9:17585-17592. [PMID: 29114682 DOI: 10.1039/c7nr06473j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
The lack of ferromagnetic (FM) van der Waals (vdW) heterostructures hinders the application of two-dimensional (2D) materials in spintronics, information memories and storage devices. Herein, we find theoretically that 2D transition-metal dichalcogenides-based vdW heterostructures, such as MoS2/VS2 and WS2/VS2, possess excellent characteristics of stable stacking configurations, FM semiconducting ground states, high Curie temperatures, staggered band alignment and a large band offset. Fortunately, 100% spin-polarized currents at the Fermi level can be achieved under certain positive external electric fields, which can filter the current into a single spin channel. Moreover, the majority channel undergoes the transition from type-II to type-I (type-III) band alignment under the negative (positive) electric field; while the band alignment of the minority channel is robust to the electric field. Our results provide a feasible way to realize 2D TMDs-based FM semiconducting heterostructures for spintronic devices.
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Affiliation(s)
- Juan Du
- Department of Physics, Henan Normal University, Xinxiang 453007, China.
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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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Zhang RW, Zhang CW, Ji WX, Yan SS, Yao YG. First-principles prediction on bismuthylene monolayer as a promising quantum spin Hall insulator. NANOSCALE 2017; 9:8207-8212. [PMID: 28580989 DOI: 10.1039/c7nr01992k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two-dimensional (2D) large band-gap topological insulators (TIs) with highly stable structures are imperative for achieving dissipationless transport devices. However, to date, only very few materials have been experimentally observed to host the quantum spin Hall (QSH) effect at low temperature, thus obstructing their potential application in practice. Using first-principles calculations, herein, we predicted a new 2D TI in the porous allotrope of a bismuth monolayer, i.e. bismuthylene, its geometrical stability was confirmed via phonon spectrum and molecular dynamics simulations. Analysis of the electronic structures reveals that bismuthylene is a native QSH state with a band gap as large as 0.28 eV at the Γ point, which is smaller than that (0.50 eV) of the buckled Bi (111) and suitable for room temperature applications. Notably, it has a much lower energy than flattened Bi and a higher energy than buckled Bi (111)…” [corrected] and flattened Bi films; thus, bismuthylene is feasible for experimental realization. Interestingly, the topological properties can be retained under strains within the range of -6%-3% and electrical fields up to 0.8 eV Å-1. A heterostructure was constructed by sandwiching bismuthylene between BN sheets, and the non-trivial topology of bismuthylene was retained with a sizable band gap. These findings provide a platform to design a large-gap QSH insulator based on the 2D bismuthylene films, which show potential applications in spintronic devices.
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Affiliation(s)
- Run-Wu Zhang
- Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, Beijing 100081, China.
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Xu B, Xiang H, Xia Y, Jiang K, Wan X, He J, Yin J, Liu Z. Monolayer AgBiP 2Se 6: an atomically thin ferroelectric semiconductor with out-plane polarization. NANOSCALE 2017; 9:8427-8434. [PMID: 28604900 DOI: 10.1039/c7nr02461d] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Using first-principles calculations, we designed a two-dimensional material, monolayer AgBiP2Se6, with the thickness of only 6 Å, which exhibited out-plane ferroelectricity. The ground state of the monolayer AgBiP2Se6 was not purely ferroelectric since the out-plane ferroelectricity originated from the compensated ferrielectric state: the off-centering antiparallel displacements of Ag+ and Bi3+ ions. The compensated ferrielectric ordering has superiority on reducing the depolarization field to stabilize the ferroelectricity. Furthermore, together with strong visible-light adsorption and suitable band edge alignments, we proposed the monolayer AgBiP2Se6 as a visible-light photocatalyst for water-splitting as the out-plane polarization could enhance the electron-hole separation. Our results offer a new way to overcome the critical thickness limitation of nanoscale ferroelectrics. The out-plane ferroelectricity in monolayer AgBiP2Se6 has great potential for developing various devices with desirable applications.
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Affiliation(s)
- Bo Xu
- National Laboratory of Solid State Microstructures and Department of Materials Science and Engineering, College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, China.
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Zhang S, Zhou W, Ma Y, Ji J, Cai B, Yang SA, Zhu Z, Chen Z, Zeng H. Antimonene Oxides: Emerging Tunable Direct Bandgap Semiconductor and Novel Topological Insulator. NANO LETTERS 2017; 17:3434-3440. [PMID: 28460176 DOI: 10.1021/acs.nanolett.7b00297] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Highly stable antimonene, as the cousin of phosphorene from group-VA, has opened up exciting realms in the two-dimensional (2D) materials family. However, pristine antimonene is an indirect band gap semiconductor, which greatly restricts its applications for optoelectronics devices. Identifying suitable materials, both responsive to incident photons and efficient for carrier transfer, is urgently needed for ultrathin devices. Herein, by means of first-principles computations we found that it is rather feasible to realize a new class of 2D materials with a direct bandgap and high carrier mobility, namely antimonene oxides with different content of oxygen. Moreover, these tunable direct bandgaps cover a wide range from 0 to 2.28 eV, which are crucial for solar cell and photodetector applications. Especially, the antimonene oxide (18Sb-18O) is a 2D topological insulator with a sizable global bandgap of 177 meV, which has a nontrivial Z2 topological invariant in the bulk and the topological states on the edge. Our findings not only introduce new vitality into 2D group-VA materials family and enrich available candidate materials in this field but also highlight the potential of these 2D semiconductors as appealing ultrathin materials for future flexible electronics and optoelectronics devices.
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Affiliation(s)
- Shengli Zhang
- Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
| | - Wenhan Zhou
- Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
| | - Yandong Ma
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig , Linnéstrasse 2, 04103 Leipzig, Germany
| | - Jianping Ji
- Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
| | - Bo Cai
- Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
| | - Shengyuan A Yang
- Research Laboratory for Quantum Materials, Singapore University of Technology and Design , Singapore 487372, Singapore
| | - Zhen Zhu
- Materials Department, University of California , Santa Barbara, California 93106, United States
| | - Zhongfang Chen
- Department of Chemistry, Institute for Functional Nanomaterials, University of Puerto Rico , Rio Piedras, San Juan PR 00931
| | - Haibo Zeng
- Key Laboratory of Advanced Display Materials and Devices, Ministry of Industry and Information Technology, College of Material Science and Engineering, Nanjing University of Science and Technology , Nanjing 210094, China
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Kou L, Ma Y, Sun Z, Heine T, Chen C. Two-Dimensional Topological Insulators: Progress and Prospects. J Phys Chem Lett 2017; 8:1905-1919. [PMID: 28394616 DOI: 10.1021/acs.jpclett.7b00222] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Two-dimensional topological insulators (2D TIs) are a remarkable class of atomically thin layered materials that exhibit unique symmetry-protected helical metallic edge states with an insulating interior. Recent years have seen a tremendous surge in research of this intriguing new state of quantum matter. In this Perspective, we summarize major milestones and the most significant progress in the latest developments of material discovery and property characterization in 2D TI research. We categorize the large number and rich variety of theoretically proposed 2D TIs based on the distinct mechanisms of topological phase transitions, and we systematically analyze and compare their structural, chemical, and physical characteristics. We assess the current status and challenges of experimental synthesis and potential device applications of 2D TIs and discuss prospects of exciting new opportunities for future research and development of this fascinating class of materials.
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Affiliation(s)
- Liangzhi Kou
- School of Chemistry, Physics and Mechanical Engineering Faculty, Queensland University of Technology , Garden Point Campus, QLD 4001, Brisbane, Australia
| | - Yandong Ma
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig , Linnéstraße 2, 04103 Leipzig, Germany
| | - Ziqi Sun
- School of Chemistry, Physics and Mechanical Engineering Faculty, Queensland University of Technology , Garden Point Campus, QLD 4001, Brisbane, Australia
| | - Thomas Heine
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig , Linnéstraße 2, 04103 Leipzig, Germany
| | - Changfeng Chen
- Department of Physics and Astronomy and High Pressure Science and Engineering Center, University of Nevada , Las Vegas, Nevada 89154, United States
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Ahn J, Yang BJ. Unconventional Topological Phase Transition in Two-Dimensional Systems with Space-Time Inversion Symmetry. PHYSICAL REVIEW LETTERS 2017; 118:156401. [PMID: 28452536 DOI: 10.1103/physrevlett.118.156401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Indexed: 06/07/2023]
Abstract
We study a topological phase transition between a normal insulator and a quantum spin Hall insulator in two-dimensional (2D) systems with time-reversal and twofold rotation symmetries. Contrary to the case of ordinary time-reversal invariant systems, where a direct transition between two insulators is generally predicted, we find that the topological phase transition in systems with an additional twofold rotation symmetry is mediated by an emergent stable 2D Weyl semimetal phase between two insulators. Here the central role is played by the so-called space-time inversion symmetry, the combination of time-reversal and twofold rotation symmetries, which guarantees the quantization of the Berry phase around a 2D Weyl point even in the presence of strong spin-orbit coupling. Pair creation and pair annihilation of Weyl points accompanying partner exchange between different pairs induces a jump of a 2D Z_{2} topological invariant leading to a topological phase transition. According to our theory, the topological phase transition in HgTe/CdTe quantum well structure is mediated by a stable 2D Weyl semimetal phase because the quantum well, lacking inversion symmetry intrinsically, has twofold rotation about the growth direction. Namely, the HgTe/CdTe quantum well can show 2D Weyl semimetallic behavior within a small but finite interval in the thickness of HgTe layers between a normal insulator and a quantum spin Hall insulator. We also propose that few-layer black phosphorus under perpendicular electric field is another candidate system to observe the unconventional topological phase transition mechanism accompanied by the emerging 2D Weyl semimetal phase protected by space-time inversion symmetry.
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Affiliation(s)
- Junyeong Ahn
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea
- Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826, Korea
| | - Bohm-Jung Yang
- Department of Physics and Astronomy, Seoul National University, Seoul 08826, Korea
- Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Korea
- Center for Theoretical Physics (CTP), Seoul National University, Seoul 08826, Korea
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Liu L, Qin H, Hu J. New type of quantum spin Hall insulators in hydrogenated PbSn thin films. Sci Rep 2017; 7:42410. [PMID: 28218297 PMCID: PMC5316964 DOI: 10.1038/srep42410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/10/2017] [Indexed: 11/09/2022] Open
Abstract
The realization of a quantum spin Hall (QSH) insulator working at high temperature is of both scientific and technical interest since it supports spin-polarized and dssipationless edge states. Based on first-principle calculations, we predicted that the two-dimensional (2D) binary compound of lead and tin (PbSn) in a buckled honeycomb framework can be tuned into a topological insulator with huge a band gap and structural stability via hydrogenation or growth on special substrates. This heavy-element-based structure is sufficiently ductile to survive the 18 ps molecular dynamics (MD) annealing to 400 K, and the band gap opened by strong spin-orbital-coupling (SOC) is as large as 0.7 eV. These characteristics indicate that hydrogenated PbSn (H-PbSn) is an excellent platform for QSH realization at high temperature.
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Affiliation(s)
- Liang Liu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Hongwei Qin
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
| | - Jifan Hu
- School of Physics, State Key Laboratory for Crystal Materials, Shandong University, Jinan 250100, China
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Jia YZ, Ji WX, Zhang CW, Zhang SF, Li P, Wang PJ. Films based on group IV–V–VI elements for the design of a large-gap quantum spin Hall insulator with tunable Rashba splitting. RSC Adv 2017. [DOI: 10.1039/c6ra28838c] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Rashba spin–orbit coupling (SOC) in topological insulators (TIs) has recently attracted significant interest due to its potential applications in spintronics.
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Affiliation(s)
- Yi-zhen Jia
- 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
| | - Shu-feng Zhang
- School of Physics and Technology
- University of Jinan
- Jinan
- People's Republic of China
| | - Ping Li
- 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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Huang H, Xu Y, Wang J, Duan W. Emerging topological states in quasi-two-dimensional materials. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2016. [DOI: 10.1002/wcms.1296] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Huaqing Huang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics; Tsinghua University; Beijing China
- Collaborative Innovation Center of Quantum Matter; Tsinghua University; Beijing China
| | - Yong Xu
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics; Tsinghua University; Beijing China
- Collaborative Innovation Center of Quantum Matter; Tsinghua University; Beijing China
- RIKEN Center for Emergent Matter Science (CEMS); Wako Japan
| | - Jianfeng Wang
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics; Tsinghua University; Beijing China
- Collaborative Innovation Center of Quantum Matter; Tsinghua University; Beijing China
| | - Wenhui Duan
- Department of Physics and State Key Laboratory of Low-Dimensional Quantum Physics; Tsinghua University; Beijing China
- Collaborative Innovation Center of Quantum Matter; Tsinghua University; Beijing China
- Institute for Advanced Study; Tsinghua University; Beijing China
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Si C, Jin KH, Zhou J, Sun Z, Liu F. Large-Gap Quantum Spin Hall State in MXenes: d-Band Topological Order in a Triangular Lattice. NANO LETTERS 2016; 16:6584-6591. [PMID: 27622311 DOI: 10.1021/acs.nanolett.6b03118] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
MXenes are a large family of two-dimensional (2D) early transition metal carbides that have shown great potential for a host of applications ranging from electrodes in supercapacitors and batteries to sensors to reinforcements in polymers. Here, on the basis of first-principles calculations, we predict that Mo2MC2O2 (M = Ti, Zr, or Hf), belonging to a recently discovered new class of MXenes with double transition metal elements in an ordered structure, are robust quantum spin Hall (QSH) insulators. A tight-binding (TB) model based on the dz2-, dxy-, and dx2-y2-orbital basis in a triangular lattice is also constructed to describe the QSH states in Mo2MC2O2. It shows that the atomic spin-orbit coupling (SOC) strength of M totally contributes to the topological gap at the Γ point, a useful feature advantageous over the usual cases where the topological gap is much smaller than the atomic SOC strength based on the classic Kane-Mele (KM) or Bernevig-Hughes-Zhang (BHZ) model. Consequently, Mo2MC2O2 show sizable gaps from 0.1 to 0.2 eV with different M atoms, sufficiently large for realizing room-temperature QSH effects. Another advantage of Mo2MC2O2 MXenes lies in their oxygen-covered surfaces which make them antioxidative and stable upon exposure to air.
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Affiliation(s)
- Chen Si
- School of Materials Science and Engineering, Beihang University , Beijing 100191, China
- Center for Integrated Computational Materials Engineering, International Research Institute for Multidisciplinary Science, Beihang University , Beijing 100191, China
| | - Kyung-Hwan Jin
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
| | - Jian Zhou
- School of Materials Science and Engineering, Beihang University , Beijing 100191, China
| | - Zhimei Sun
- School of Materials Science and Engineering, Beihang University , Beijing 100191, China
- Center for Integrated Computational Materials Engineering, International Research Institute for Multidisciplinary Science, Beihang University , Beijing 100191, China
| | - Feng Liu
- Department of Materials Science and Engineering, University of Utah , Salt Lake City, Utah 84112, United States
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A new kind of 2D topological insulators BiCN with a giant gap and its substrate effects. Sci Rep 2016; 6:30003. [PMID: 27444954 PMCID: PMC4956758 DOI: 10.1038/srep30003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 06/27/2016] [Indexed: 11/24/2022] Open
Abstract
Based on DFT calculation, we predict that BiCN, i.e., bilayer Bi films passivated with -CN group, is a novel 2D Bi-based material with highly thermodynamic stability, and demonstrate that it is also a new kind of 2D TI with a giant SOC gap (~1 eV) by direct calculation of the topological invariant Z2 and obvious exhibition of the helical edge states. Monolayer h-BN and MoS2 are identified as good candidate substrates for supporting the nontrivial topological insulating phase of the 2D TI films, since the two substrates can stabilize and weakly interact with BiCN via van der Waals interaction and thus hardly affect the electronic properties, especially the band topology. The topological properties are robust against the strain and electric field. This may provide a promising platform for realization of novel topological phases.
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Exploring Ag(111) Substrate for Epitaxially Growing Monolayer Stanene: A First-Principles Study. Sci Rep 2016; 6:29107. [PMID: 27373464 PMCID: PMC4931515 DOI: 10.1038/srep29107] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 06/01/2016] [Indexed: 11/30/2022] Open
Abstract
Stanene, a two-dimensional topological insulator composed of Sn atoms in a hexagonal lattice, is a promising contender to Si in nanoelectronics. Currently it is still a significant challenge to achieve large-area, high-quality monolayer stanene. We explore the potential of Ag(111) surface as an ideal substrate for the epitaxial growth of monolayer stanene. Using first-principles calculations, we study the stability of the structure of stanene in different epitaxial relations with respect to Ag(111) surface, and also the diffusion behavior of Sn adatom on Ag(111) surface. Our study reveals that: (1) the hexagonal structure of stanene monolayer is well reserved on Ag(111) surface; (2) the height of epitaxial stanene monolayer is comparable to the step height of the substrate, enabling the growth to cross the surface step and achieve a large-area stanene; (3) the perfect lattice structure of free-standing stanene can be achieved once the epitaxial stanene monolayer is detached from Ag(111) surface; and finally (4) the diffusion barrier of Sn adatom on Ag(111) surface is found to be only 0.041 eV, allowing the epitaxial growth of stanene monolayer even at low temperatures. Our above revelations strongly suggest that Ag(111) surface is an ideal candidate for growing large-area, high-quality monolayer stanene.
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Ren Y, Qiao Z, Niu Q. Topological phases in two-dimensional materials: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:066501. [PMID: 27176924 DOI: 10.1088/0034-4885/79/6/066501] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Topological phases with insulating bulk and gapless surface or edge modes have attracted intensive attention because of their fundamental physics implications and potential applications in dissipationless electronics and spintronics. In this review, we mainly focus on recent progress in the engineering of topologically nontrivial phases (such as [Formula: see text] topological insulators, quantum anomalous Hall effects, quantum valley Hall effects etc) in two-dimensional systems, including quantum wells, atomic crystal layers of elements from group III to group VII, and the transition metal compounds.
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Affiliation(s)
- Yafei Ren
- 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, People's Republic of China. CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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Huang C, Zhou J, Wu H, Deng K, Jena P, Kan E. Quantum Phase Transition in Germanene and Stanene Bilayer: From Normal Metal to Topological Insulator. J Phys Chem Lett 2016; 7:1919-1924. [PMID: 27149183 DOI: 10.1021/acs.jpclett.6b00651] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Two-dimensional (2D) topological insulators (TIs) that exhibit quantum spin Hall effects are a new class of materials with conducting edge and insulating bulk. The conducting edge bands are spin-polarized, free of back scattering, and protected by time-reversal symmetry with potential for high-efficiency applications in spintronics. On the basis of first-principles calculations, we show that under external pressure recently synthesized stanene and germanene buckled bilayers can automatically convert into a new dynamically stable phase with flat honeycomb meshes. In contrast with the active surfaces of buckled bilayer of stanene or germanene, the above new phase is chemically inert. Furthermore, we demonstrate that these flat bilayers are 2D TIs with sizable topologically nontrivial band gaps of ∼0.1 eV, which makes them viable for room-temperature applications. Our results suggest some new design principles for searching stable large-gap 2D TIs.
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Affiliation(s)
- Chengxi Huang
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Jian Zhou
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Haiping Wu
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
| | - Kaiming Deng
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
| | - Puru Jena
- Department of Physics, Virginia Commonwealth University , Richmond, Virginia 23284, United States
| | - Erjun Kan
- Department of Applied Physics and Key Laboratory of Soft Chemistry and Functional Materials (Ministry of Education), Nanjing University of Science and Technology , Nanjing, Jiangsu 210094, P. R. China
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50
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Liu PF, Zhou L, Frauenheim T, Wu LM. New quantum spin Hall insulator in two-dimensional MoS2 with periodically distributed pores. NANOSCALE 2016; 8:4915-4921. [PMID: 26877231 DOI: 10.1039/c5nr08842a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
MoS2, one of the transition metal dichalcogenides (TMDs), has gained a lot of attention due to its excellent semiconductor characteristics and potential applications. Here, based on density functional theory methods, we predict a novel 2D QSH insulator in the porous allotrope of monolayer MoS2 (g-MoS2), consisting of MoS2 squares and hexagons. g-MoS2 has a nontrivial gap as large as 109 meV, comparable with previously reported 1T'-MoS2 (80 meV) and so-MoS2 (25 meV). We demonstrate that the origin of the 2D QSH effect in g-MoS2 originates from the pure d-d band inversion, different from the conventional band inversion between s-p, p-p or d-p orbitals. The new polymorph greatly enriches the TMD family and its stabilities are confirmed using phonon spectrum analysis. In particular, its porous structure endows it with the potential for efficient gas separation and energy storage applications.
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Affiliation(s)
- Peng-Fei Liu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China. and University of Chinese Academy of Sciences, Beijing 100039, People's Republic of China
| | - Liujiang Zhou
- Bremen Center for Computational Materials Science, University of Bremen, Am Falturm 1, 28359 Bremen, Germany. and Max Planck Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, 01187 Dresden, Germany
| | - Thomas Frauenheim
- Bremen Center for Computational Materials Science, University of Bremen, Am Falturm 1, 28359 Bremen, Germany.
| | - Li-Ming Wu
- State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, People's Republic of China.
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