1
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Hussain G, Cuono G, Dziawa P, Janaszko D, Sadowski J, Kret S, Kurowska B, Polaczyński J, Warda K, Sattar S, Canali CM, Lau A, Brzezicki W, Story T, Autieri C. Pentagonal nanowires from topological crystalline insulators: a platform for intrinsic core-shell nanowires and higher-order topology. NANOSCALE HORIZONS 2024; 9:1290-1300. [PMID: 38804204 DOI: 10.1039/d4nh00019f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
We report on the experimental realization of Pb1-xSnx Te pentagonal nanowires (NWs) with [110] orientation using molecular beam epitaxy techniques. Using first-principles calculations, we investigate the structural stability of NWs of SnTe and PbTe in three different structural phases: cubic, pentagonal with [001] orientation and pentagonal with [110] orientation. Within a semiclassical approach, we show that the interplay between ionic and covalent bonds favors the formation of pentagonal NWs. Additionally, we find that this pentagonal structure is more likely to occur in tellurides than in selenides. The disclination and twin boundary cause the electronic states originating from the NW core region to generate a conducting band connecting the valence and conduction bands, creating a symmetry-enforced metallic phase. The metallic core band has opposite slopes in the cases of Sn and Te twin boundaries, while the bands from the shell are insulating. We finally study the electronic and topological properties of pentagonal NWs unveiling their potential as a new platform for higher-order topology and fractional charge. These pentagonal NWs represent a unique case of intrinsic core-shell one-dimensional nanostructures with distinct structural, electronic and topological properties between the core and the shell region.
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Affiliation(s)
- Ghulam Hussain
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Giuseppe Cuono
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- Consiglio Nazionale delle Ricerche (CNR-SPIN), Unitá di Ricerca presso Terzi c/o Universitá "G. DAnnunzio", 66100 Chieti, Italy
| | - Piotr Dziawa
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Dorota Janaszko
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Janusz Sadowski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Slawomir Kret
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Bogusława Kurowska
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Jakub Polaczyński
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Kinga Warda
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Gdańsk 80-233, Poland
| | - Shahid Sattar
- Department of Physics and Electrical Engineering, Linnaeus University, 392 31 Kalmar, Sweden
| | - Carlo M Canali
- Department of Physics and Electrical Engineering, Linnaeus University, 392 31 Kalmar, Sweden
| | - Alexander Lau
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Wojciech Brzezicki
- Institute of Theoretical Physics, Jagiellonian University, ulica S. ojasiewicza 11, PL-30348 Kraków, Poland
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Tomasz Story
- Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland
| | - Carmine Autieri
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, PL-02668 Warsaw, Poland.
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2
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Mientjes MGC, Guan X, Lueb PJH, Verheijen MA, Bakkers EPAM. Catalyst-free MBE growth of PbSnTe nanowires with tunable aspect ratio. NANOTECHNOLOGY 2024; 35:325602. [PMID: 38710174 DOI: 10.1088/1361-6528/ad47c8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Accepted: 05/06/2024] [Indexed: 05/08/2024]
Abstract
Topological crystalline insulators (TCIs) are interesting for their topological surface states, which hold great promise for scattering-free transport channels and fault-tolerant quantum computing. A promising TCI is SnTe. However, Sn-vacancies form in SnTe, causing a high hole density, hindering topological transport from the surface being measured. This issue could be relieved by using nanowires with a high surface-to-volume ratio. Furthermore, SnTe can be alloyed with Pb reducing the Sn-vacancies while maintaining its topological phase. Here we present the catalyst-free growth of monocrystalline PbSnTe in molecular beam epitaxy. By the addition of a pre-deposition stage before the growth, we have control over the nucleation phase and thereby increase the nanowire yield. This facilitates tuning the nanowire aspect ratio by a factor of four by varying the growth parameters. These results allow us to grow specific morphologies for future transport experiments to probe the topological surface states in a Pb1-xSnxTe-based platform.
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Affiliation(s)
| | - Xin Guan
- Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
| | - Pim J H Lueb
- Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
| | - Marcel A Verheijen
- Eindhoven University of Technology, 5600MB Eindhoven, The Netherlands
- Eurofins Materials Science Eindhoven, 5656AE Eindhoven, The Netherlands
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3
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Hussain G, Warda K, Cuono G, Autieri C. Density Functional Theory Study of the Spin-Orbit Insulating Phase in SnTe Cubic Nanowires: Implications for Topological Electronics. ACS APPLIED NANO MATERIALS 2024; 7:8044-8052. [PMID: 38633298 PMCID: PMC11019662 DOI: 10.1021/acsanm.4c00506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 03/06/2024] [Accepted: 03/07/2024] [Indexed: 04/19/2024]
Abstract
We investigate the electronic, structural, and topological properties of the SnTe and PbTe cubic nanowires using ab initio calculations. Using standard and linear-scale density functional theory, we go from the ultrathin limit up to the nanowire thicknesses observed experimentally. Finite-size effects in the ultrathin limit produce an electric quadrupole and associated structural distortions; these distortions increase the band gap, but they get reduced with the size of the nanowires and become less and less relevant. Ultrathin SnTe cubic nanowires are trivial band gap insulators; we demonstrate that by increasing the thickness, there is an electronic transition to a spin-orbit insulating phase due to trivial surface states in the regime of thin nanowires. These trivial surface states with a spin-orbit gap of a few meV appear at the same k-point of the topological surface states. Going to the limit of thick nanowires, we should observe the transition to the topological crystalline insulator phase with the presence of two massive surface Dirac fermions hybridized with the persistent trivial surface states. Therefore, we have the copresence of massive Dirac surface states and trivial surface states close to the Fermi level in the same region of the k-space. According to our estimation, the cubic SnTe nanowires are trivial insulators below the critical thickness tc1 = 10 nm, and they become spin-orbit insulators between tc1 = 10 nm and tc2 = 17 nm, while they transit to the topological phase above the critical thickness of tc2 = 17 nm. These critical thickness values are in the range of typical experimental thicknesses, making the thickness a relevant parameter for the synthesis of topological cubic nanowires. Pb1-xSnxTe nanowires would have both these critical thicknesses tc1 and tc2 at larger values depending on the doping concentration. We discuss the limitations of density functional theory in the context of topological nanowires and the consequences of our results on topological electronics.
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Affiliation(s)
- Ghulam Hussain
- International
Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, Warsaw PL-02668, Poland
- Institute
for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Kinga Warda
- International
Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, Warsaw PL-02668, Poland
- Faculty
of Applied Physics and Mathematics, Gdansk
University of Technology, Gdańsk 80-233, Poland
| | - Giuseppe Cuono
- International
Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, Warsaw PL-02668, Poland
| | - Carmine Autieri
- International
Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, Warsaw PL-02668, Poland
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4
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Li J, Wang XT, Chen YQ, Wei YH, Yuan HK, Tian CL. Prediction of a two-dimensional high Curie temperature Weyl nodal line kagome semimetal. Phys Chem Chem Phys 2024; 26:3092-3100. [PMID: 38180442 DOI: 10.1039/d3cp03762b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2024]
Abstract
Kagome lattices may have numerous exotic physical properties, such as stable ferromagnetism and topological states. Herein, combining the particle swarm structure search method with first-principles calculations, we identify a two-dimensional (2D) kagome Mo2Se3 crystal structure with space group P6/mmm. The results show that 2D kagome Mo2Se3 is a 100% spin-polarized topological nodal line semimetal and exhibits excellent ambient stability. The band crossing points form two nodal loops around the high-symmetry points Γ and K. On the other hand, Mo2Se3 shows intrinsic ferromagnetism with a large magnetic moment of 3.05 μB per Mo atom and magnetic anisotropy energy (MAE) of 4.78 meV. Monte Carlo simulations estimate that Mo2Se3 possesses a high Curie temperature of about 673 K. In addition, its ferromagnetic ground state can be well preserved under external strain, and the MAE can be improved by increasing the strain. More importantly, the position of each nodal line can be adjusted to the Fermi level through hole doping. This multifunctional 2D magnetic material that combines spin and topology has great potential in the field of nanoscale spintronic devices.
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Affiliation(s)
- Jie Li
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Xiao-Tian Wang
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Ya-Qing Chen
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Yu-Hao Wei
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Hong-Kuan Yuan
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
| | - Chun-Ling Tian
- School of Physical Science and Technology, Southwest University, Chongqing 400715, China.
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Su Y, Ding C, Yao Y, Fu R, Xue M, Liu X, Lin J, Wang F, Zhan X, Wang Z. Orietation-controlled synthesis and Raman study of 2D SnTe. NANOTECHNOLOGY 2023; 34:505206. [PMID: 37729885 DOI: 10.1088/1361-6528/acfb8b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/20/2023] [Indexed: 09/22/2023]
Abstract
Tin telluride (SnTe), as a narrow bandgap semiconductor material, has great potential for developing photodetectors with wide spectra and ultra-fast response. At the same time, it is also an important topological crystal insulator material, with different topological surface states on several common surfaces. Here, we introduce different Sn sources and control the growth of regular SnTe nanosheets along the (100) and (111) planes through the atmospheric pressure chemical vapor deposition method. It has been proven through various characterizations that the synthesized SnTe is a high-quality single crystal. In addition, the angular resolved Raman spectra of SnTe nanosheets grown on different crystal planes are first demonstrated. The experimental results showed that square SnTe nanosheets grown along the (100) plane exhibit in-plane anisotropy. At the same time, we use micro-nanofabrication technology to manufacture SnTe-based field effect transistors and photodetectors to explore their electrical and optoelectronic properties. It has been confirmed that transistors based on grown SnTe nanosheets exhibit p-type semiconductor characteristics and have a high response to infrared light. This work provides a new approach for the controllable synthesis of SnTe and adds new content to the research of SnTe-based infrared detectors.
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Affiliation(s)
- Yanfei Su
- Department of Physics, Shanghai University of Electric Power, Shanghai 201306, People's Republic of China
- National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Chuyun Ding
- Department of Physics, Shanghai University of Electric Power, Shanghai 201306, People's Republic of China
- National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Yuyu Yao
- National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Rao Fu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Mengfei Xue
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, People's Republic of China
- University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Xiaolin Liu
- Department of Physics, Shanghai University of Electric Power, Shanghai 201306, People's Republic of China
| | - Jia Lin
- Department of Physics, Shanghai University of Electric Power, Shanghai 201306, People's Republic of China
| | - Feng Wang
- National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Xueying Zhan
- National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
| | - Zhenxing Wang
- National Center for Nanoscience and Technology, Beijing 100190, People's Republic of China
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing 100049, People's Republic of China
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6
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Akiyama R, Ishikawa R, Akutsu-Suyama K, Nakanishi R, Tomohiro Y, Watanabe K, Iida K, Mitome M, Hasegawa S, Kuroda S. Direct Probe of the Ferromagnetic Proximity Effect at the Interface of SnTe/Fe Heterostructure by Polarized Neutron Reflectometry. J Phys Chem Lett 2022; 13:8228-8235. [PMID: 36031713 DOI: 10.1021/acs.jpclett.2c01478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Introducing magnetic order into a topological insulator (TI) system has attracted much attention with an expectation of realizing exotic phenomena such as the quantum anomalous Hall effect (QAHE) and axion insulator states. The magnetic proximity effect (MPE) is one of the promising schemes to induce the magnetic order on the surface of a TI without introducing disorder accompanied by doping magnetic impurities in the TI. In this study, we investigate the MPE at the interface of a heterostructure consisting of the topological crystalline insulator (TCI) SnTe and Fe by employing polarized neutron reflectometry. The ferromagnetic order penetrates ∼2.2 nm deep into the SnTe layer from the interface with Fe, which persists up to room temperature. This is induced by the MPE on the surface of the TCI preserving the coherent topological states without introducing the disorder by doping magnetic impurities. This would open up a way for realizing next-generation spintronics and quantum computational devices.
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Affiliation(s)
- Ryota Akiyama
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ryo Ishikawa
- Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
| | - Kazuhiro Akutsu-Suyama
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Ryosuke Nakanishi
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yuta Tomohiro
- Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
| | - Kazumi Watanabe
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kazuki Iida
- Neutron Science and Technology Center, Comprehensive Research Organization for Science and Society (CROSS), 162-1 Shirakata, Tokai, Ibaraki 319-1106, Japan
| | - Masanori Mitome
- Electron Microscopy Analysis Station, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Shuji Hasegawa
- Department of Physics, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shinji Kuroda
- Institute of Materials Science, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8573, Japan
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7
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Song L, Tang L, Hao Q, Teng KS, Lv H, Wang J, Feng J, Zhou Y, He W, Wang W. Broadband photodetector based on SnTe nanofilm/n-Ge heterostructure. NANOTECHNOLOGY 2022; 33:425203. [PMID: 35830829 DOI: 10.1088/1361-6528/ac80cc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 07/13/2022] [Indexed: 06/15/2023]
Abstract
Combining novel two-dimensional materials with traditional semiconductors to form heterostructures for photoelectric detection have attracted great attention due to their excellent photoelectric properties. In this study, we reported the formation of a heterostructure comprising of tin telluride (SnTe) and germanium (Ge) by a simple and efficient one-step magnetron sputtering technique. A photodetector was fabricated by sputtering a nanofilm of SnTe on to a pre-masked n-Ge substrate.J-Vmeasurements obtained from the SnTe/n-Ge photodetector demonstrated diode and photovoltaic characteristics in the visible to near-infrared (NIR) band (i.e. 400-2050 nm). Under NIR illumination at 850 nm with an optical power density of 13.81 mW cm-2, the SnTe/n-Ge photodetector exhibited a small open-circuit voltage of 0.05 V. It also attained a high responsivity (R) and detectivity (D*) of 617.34 mA W-1(at bias voltage of -0.5 V) and 2.33 × 1011cmHz1/2W-1(at zero bias), respectively. Therefore, SnTe nanofilm/n-Ge heterostructure is highly suitable for used as low-power broadband photodetector due to its excellent performances and simple device configuration.
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Affiliation(s)
- Liyuan Song
- The Laboratory of Photonics Information Technology, Ministry of Industry and Information Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
- Yunnan Key Laboratory of Advanced Photoelectronic Materials & Devices, Kunming 650223, People's Republic of China
| | - Libin Tang
- The Laboratory of Photonics Information Technology, Ministry of Industry and Information Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
- Yunnan Key Laboratory of Advanced Photoelectronic Materials & Devices, Kunming 650223, People's Republic of China
| | - Qun Hao
- The Laboratory of Photonics Information Technology, Ministry of Industry and Information Technology, School of Optics and Photonics, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Kar Seng Teng
- Department of Electronic and Electrical Engineering, Swansea University, Bay Campus, Fabian Way, Swansea SA1 8EN, United Kingdom
| | - Hao Lv
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
| | - Jingyu Wang
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
| | - Jiangmin Feng
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
| | - Yan Zhou
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
| | - Wenjin He
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
| | - Wei Wang
- Kunming Institute of Physics, Kunming 650223, People's Republic of China
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8
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Huang SM, Lin C, You SY, Yan YJ, Yu SH, Chou M. The quantum oscillations in different probe configurations in the [Formula: see text] topological insulator macroflake. Sci Rep 2022; 12:5191. [PMID: 35338190 PMCID: PMC8956641 DOI: 10.1038/s41598-022-09073-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/10/2022] [Indexed: 11/08/2022] Open
Abstract
We demonstrate quantum oscillations in [Formula: see text] topological insulator macroflakes in different probe configurations. The oscillation period in the local configuration is twice compared to the non-local configuration. The Aharonov-Bohm-like (AB-like) oscillation dominates the transport property in the local configuration and the Altshuler-Aronov-Spivak-like (AAS-like) oscillation dominates the transport property in the non-local configuration. The AB-like oscillation period is 0.21 T and the related loop diameter is 156 nm which is consistent with the reported phase coherence length in topological insulators. The Shubnikov-de Haas oscillation frequency is the same but oscillation peaks reveal a [Formula: see text] phase shift in the local and non-local configuration. The Berry phase is [Formula: see text] in the local configuration and 0 in non-local configuration.
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Affiliation(s)
- Shiu-Ming Huang
- Department of Physics, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
- Center of Crystal Research, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, TCECM, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
| | - Chien Lin
- Department of Physics, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
| | - Sheng-Yu You
- Department of Physics, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
| | - You-Jhih Yan
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
| | - Shih-Hsun Yu
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
| | - Mitch Chou
- Center of Crystal Research, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
- Department of Materials and Optoelectronic Science, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
- Taiwan Consortium of Emergent Crystalline Materials, TCECM, National Sun Yat-Sen University, Kaohsiung, 80424 Taiwan
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9
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Paz WS, Menezes MG, Batista NN, Sanchez-Santolino G, Velický M, Varela M, Capaz RB, Palacios JJ. Franckeite as an Exfoliable Naturally Occurring Topological Insulator. NANO LETTERS 2021; 21:7781-7788. [PMID: 34461016 DOI: 10.1021/acs.nanolett.1c02742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Franckeite is a natural superlattice composed of two alternating layers of different composition which has shown potential for optoelectronic applications. In part, the interest in franckeite lies in its layered nature which makes it easy to exfoliate into very thin heterostructures. Not surprisingly, its chemical composition and lattice structure are so complex that franckeite has escaped screening protocols and high-throughput searches of materials with nontrivial topological properties. On the basis of density functional theory calculations, we predict a quantum phase transition originating from stoichiometric changes in one of franckeite composing layers (the quasihexagonal one). While for a large concentration of Sb, franckeite is a sequence of type-II semiconductor heterojunctions, for a large concentration of Sn, these turn into type-III, much alike InAs/GaSb artificial heterojunctions, and franckeite becomes a strong topological insulator. Transmission electron microscopy observations confirm that such a phase transition may actually occur in nature.
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Affiliation(s)
- Wendel S Paz
- Departamento de Física, Universidade Federal do Espírito Santo, Vitória, ES 29075-910, Brazil
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
| | - Marcos G Menezes
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
| | - Nathanael N Batista
- Departamento de Física, Universidade Federal do Espírito Santo, Vitória, ES 29075-910, Brazil
- Instituto Federal do Espirito Santo, Cariacica, ES 29150-410, Brazil
| | - Gabriel Sanchez-Santolino
- Facultad de Ciencias Físicas & Instituto Plurisciplinar. Universidad Complutense de Madrid 28040 Madrid, Spain
| | - Matěj Velický
- J. Heyrovský Institute of Physical Chemistry, Czech Academy of Sciences, Dolejškova 2155/3, 182 23 Prague 8, Czech Republic
| | - María Varela
- Facultad de Ciencias Físicas & Instituto Plurisciplinar. Universidad Complutense de Madrid 28040 Madrid, Spain
| | - Rodrigo B Capaz
- Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, Rio de Janeiro, RJ 21941-972, Brazil
| | - Juan José Palacios
- Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera (INC), and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain
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10
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Münning F, Breunig O, Legg HF, Roitsch S, Fan D, Rößler M, Rosch A, Ando Y. Quantum confinement of the Dirac surface states in topological-insulator nanowires. Nat Commun 2021; 12:1038. [PMID: 33589609 PMCID: PMC7884718 DOI: 10.1038/s41467-021-21230-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 01/17/2021] [Indexed: 11/20/2022] Open
Abstract
The non-trivial topology of three-dimensional topological insulators dictates the appearance of gapless Dirac surface states. Intriguingly, when made into a nanowire, quantum confinement leads to a peculiar gapped Dirac sub-band structure. This gap is useful for, e.g., future Majorana qubits based on TIs. Furthermore, these sub-bands can be manipulated by a magnetic flux and are an ideal platform for generating stable Majorana zero modes, playing a key role in topological quantum computing. However, direct evidence for the Dirac sub-bands in TI nanowires has not been reported so far. Here, using devices fabricated from thin bulk-insulating (Bi1-xSbx)2Te3 nanowires we show that non-equidistant resistance peaks, observed upon gate-tuning the chemical potential across the Dirac point, are the unique signatures of the quantized sub-bands. These TI nanowires open the way to address the topological mesoscopic physics, and eventually the Majorana physics when proximitized by an s-wave superconductor.
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Affiliation(s)
- Felix Münning
- Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany
| | - Oliver Breunig
- Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany
| | - Henry F Legg
- Institute for Theoretical Physics, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany
- Department of Physics, University of Basel, Klingelbergstrasse 82, CH-4056, Basel, Switzerland
| | - Stefan Roitsch
- Institute of Physical Chemistry, University of Cologne, Luxemburger Str. 116, 50939, Köln, Germany
| | - Dingxun Fan
- Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany
| | - Matthias Rößler
- Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany
| | - Achim Rosch
- Institute for Theoretical Physics, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany
| | - Yoichi Ando
- Physics Institute II, University of Cologne, Zülpicher Str. 77, 50937, Köln, Germany.
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11
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Robinson F, Newbrook DW, Curran P, de Groot CHK, Hardie D, Hector AL, Huang R, Reid G. Low temperature CVD of thermoelectric SnTe thin films from the single source precursor, [ nBu 3Sn(Te nBu)]. Dalton Trans 2021; 50:998-1006. [PMID: 33355323 DOI: 10.1039/d0dt03760e] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work has demonstrated that the single source precursor [nBu3Sn(TenBu)], bearing n-butyl groups and containing the necessary 1 : 1 Sn : Te ratio, facilitates growth of continuous, stoichiometric SnTe thin films. This single source CVD precursor allows film growth at significantly lower temperatures (355-434 °C at 0.01-0.05 Torr) than required for CVD from SnTe powder. This could be advantageous for controlling the surface states in topological insulators. The temperature-dependent thermoelectric performance of these films has been determined, revealing them to be p-type semiconductors with peak Seebeck coefficient and power factor values of 78 μV K-1 and 8.3 μW K-2 cm-1, respectively, at 615 K; comparing favourably with data from bulk SnTe. Further, we have demonstrated that the precursor facilitates area selective growth of SnTe onto the TiN regions of SiO2/TiN patterned substrates, which is expected to be beneficial for the fabrication of micro-thermoelectric generators.
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Affiliation(s)
- Fred Robinson
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - Daniel W Newbrook
- School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Peter Curran
- Deregallera Ltd, Unit 2, De Clare Court, Pontygwindy Industrial Estate, Caerphilly CF83 3HU, UK
| | - C H Kees de Groot
- School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Duncan Hardie
- Deregallera Ltd, Unit 2, De Clare Court, Pontygwindy Industrial Estate, Caerphilly CF83 3HU, UK
| | - Andrew L Hector
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
| | - Ruomeng Huang
- School of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK
| | - Gillian Reid
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK.
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12
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Liu H, Liu Y, Dong S, Xu H, Wu Y, Hao L, Cao B, Li M, Wang Z, Han Z, Yan K. Photothermoelectric SnTe Photodetector with Broad Spectral Response and High On/Off Ratio. ACS APPLIED MATERIALS & INTERFACES 2020; 12:49830-49839. [PMID: 33095577 DOI: 10.1021/acsami.0c15639] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A broadband photodetector with high performance is highly desirable for the optoelectric and sensing application. Herein, we report a "photo-thermo-electric" (PTE) detector based on an ultrathin SnTe film. The (001)-oriented SnTe films with the wafer size scale are epitaxially grown on the surface of sodium chloride crystals by a scalable sputtering method. Due to the giant PTE effect under laser spot excitation on the asymmetric position between two terminals, a built-in electrical field is produced to drive bulk carriers for a self-powered photodetector, leading to a broad spectral response in the wavelength range from 404 nm to 10.6 μm far beyond the limitation of the energy band gap. Significantly, the photodetector displays a high on/off photoswitching ratio of over 105 with a suppressed dark current, which is 4-5 orders of magnitude higher than that of other reported SnTe-based detectors. Under zero external bias, the device yields the highest detectivity of ∼1.3 × 1010 cm Hz1/2 W-1 with a corresponding responsivity of ∼3.9 mA W-1 and short rising/falling times of ∼78/84 ms. Furthermore, the photodetector transferred onto the flexible template exhibits excellent mechanical flexibility over 300 bending cycles. These findings offer feasible strategies toward designing and developing low-power-consumption wearable optoelectronics with competitive performance.
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Affiliation(s)
- Hui Liu
- School of Materials Science and Engineering, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Yunjie Liu
- College of Science, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Shichang Dong
- School of Materials Science and Engineering, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Hanyang Xu
- School of Materials Science and Engineering, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Yupeng Wu
- School of Materials Science and Engineering, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Lanzhong Hao
- School of Materials Science and Engineering, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Banglin Cao
- College of Materials Science and Engineering, Sichuan University, Chengdu, Sichuan 610065, People's Republic of China
| | - Mingjie Li
- School of Environment and Energy, State Key 426 Laboratory of Luminescent Materials and Devices, South China University of Technology, 429 Guangzhou, Guangdong 510006, People's Republic of China
| | - Zegao Wang
- College of Materials Science and Engineering, Sichuan University, Chengdu, Sichuan 610065, People's Republic of China
| | - Zhide Han
- School of Materials Science and Engineering, China University of Petroleum, Qingdao, Shandong 266580, People's Republic of China
| | - Keyou Yan
- School of Environment and Energy, State Key 426 Laboratory of Luminescent Materials and Devices, South China University of Technology, 429 Guangzhou, Guangdong 510006, People's Republic of China
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13
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Liu J, Li X, Wang H, Yuan G, Suvorova A, Gain S, Ren Y, Lei W. Ultrathin High-Quality SnTe Nanoplates for Fabricating Flexible Near-Infrared Photodetectors. ACS APPLIED MATERIALS & INTERFACES 2020; 12:31810-31822. [PMID: 32585086 DOI: 10.1021/acsami.0c07847] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
This work demonstrates a controlled van der Waals growth of two-dimensional SnTe nanoplates on mica substrates and their applications in flexible near-infrared photodetectors. The growth of nonlayered rock-salt structured SnTe crystals into two-dimensional SnTe nanoplate structures is mainly caused by the two-dimensional nature of the mica surface, which also results in the ultrathin nanoplates obtained (3.6 nm, equivalent to 6 monolayers). Furthermore, it is found that the shape of the SnTe nanoplates can be well engineered by changing their growth temperature due to the competition between the surface energy of the {100} crystallographic plane and that of the {111} plane. As a result of the favorable physical properties of topological crystalline insulators such as metallic surface (high electron mobility) and narrow bandgap, near-infrared photodetectors based on single SnTe nanoplate with the thickness of 3.6 nm present excellent device performance with a responsivity of 698 mA/W, a specific detectivity of 3.89 × 108 jones, and an external quantum efficiency of 88.5% under the illumination of a 980 nm laser at room temperature (300 K) without applying a gate voltage (Vg). Upon increasing the gate voltage from -30 to 30 V, the detector responsivity increases from 2.96 to 723 mA/W and the detector detectivity increases from 2.4 × 106 to 5.3 × 108 jones. Furthermore, upon increasing the thickness of SnTe nanoplate from 3.6 to 35 nm, the detector responsivity increases from 0.698 to 1.468 A/W. The device performance measured after bending for 300 times as well as after bending with different radii presents no obvious degradation, which exhibits the excellent flexibility of the SnTe nanoplate detectors. These results not only contribute to a deep understanding of the mechanisms of the van der Waals growth of nonlayered materials into two-dimensional structure but also demonstrate the immense potential of SnTe nanoplates to be used in flexible near-infrared detectors.
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Affiliation(s)
- Junliang Liu
- Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - Xiao Li
- Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - Han Wang
- Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - Guang Yuan
- College of Information Science and Engineering, Ocean University of China, Qingdao 266100, China
| | - Alexandra Suvorova
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - Sarah Gain
- Centre for Microscopy, Characterisation and Analysis, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - Yongling Ren
- Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
| | - Wen Lei
- Department of Electrical, Electronic and Computer Engineering, The University of Western Australia, 35 Stirling Highway, Crawley 6009, Australia
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14
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Liu CW, Wang Z, Qiu RLJ, Gao XPA. Development of topological insulator and topological crystalline insulator nanostructures. NANOTECHNOLOGY 2020; 31:192001. [PMID: 31962300 DOI: 10.1088/1361-6528/ab6dfc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Topological insulators (TIs), a class of quantum materials with time reversal symmetry protected gapless Dirac-surface states, have attracted intensive research interests due to their exotic electronic properties. Topological crystalline insulators (TCIs), whose gapless surface states are protected by the crystal symmetry, have recently been proposed and experimentally verified as a new class of TIs. With high surface-to-volume ratio, nanoscale TI and TCI materials such as nanowires and nanoribbons can have significantly enhanced contribution from surface states in carrier transport and are thus ideally suited for the fundamental studies of topologically protected surface state transport and nanodevice fabrication. This article will review the synthesis and transport device measurements of TIs and TCIs nanostructures.
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Affiliation(s)
- Chieh-Wen Liu
- Department of Physics, Case Western Reserve University, 2076 Adelbert Road, Cleveland, OH 44106, United States of America
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15
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Wang AQ, Ye XG, Yu DP, Liao ZM. Topological Semimetal Nanostructures: From Properties to Topotronics. ACS NANO 2020; 14:3755-3778. [PMID: 32286783 DOI: 10.1021/acsnano.9b07990] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Characterized by bulk Dirac or Weyl cones and surface Fermi-arc states, topological semimetals have sparked enormous research interest in recent years. The nanostructures, with large surface-to-volume ratio and easy field-effect gating, provide ideal platforms to detect and manipulate the topological quantum states. Exotic physical properties originating from these topological states endow topological semimetals attractive for future topological electronics (topotronics). For example, the linear energy dispersion relation is promising for broadband infrared photodetectors, the spin-momentum locking nature of topological surface states is valuable for spintronics, and the topological superconductivity is highly desirable for fault-tolerant qubits. For real-life applications, topological semimetals in the form of nanostructures are necessary in terms of convenient fabrication and integration. Here, we review the recent progresses in topological semimetal nanostructures and start with the quantum transport properties. Then topological semimetal-based electronic devices are introduced. Finally, we discuss several important aspects that should receive great effort in the future, including controllable synthesis, manipulation of quantum states, topological field effect transistors, spintronic applications, and topological quantum computation.
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Affiliation(s)
- An-Qi Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xing-Guo Ye
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Da-Peng Yu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
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16
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Lu W, He T, Li S, Zuo X, Zheng Y, Lou X, Zhang J, Li D, Liu J, Tang G. Thermoelectric performance of nanostructured In/Pb codoped SnTe with band convergence and resonant level prepared via a green and facile hydrothermal method. NANOSCALE 2020; 12:5857-5865. [PMID: 32101245 DOI: 10.1039/d0nr00495b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
SnTe is considered as a promising alternative to the conventional high-performance thermoelectric material PbTe, which inspired the thermoelectric community for a while. Here, we design a green, facile and low-energy-intensity hydrothermal route without involving any toxic or unstable chemicals to fabricate SnTe-based thermoelectric materials. Ultralow lattice thermal conductivity and enhanced thermoelectric performance are achieved via the combination of band engineering and nanostructuring. Enhanced Seebeck coefficient and power factor are induced by converging the band structure and creating resonant levels due to Pb and In doping. More importantly, due to the reduced grain sizes, nanoparticles, and dual-atom point defect scattering, ultralow lattice thermal conductivity was obtained in the bulk samples fabricated by the hydrothermal route. Benefiting from the enhanced power factor and significantly reduced thermal conductivity, the peak ZT is enhanced to ∼0.7 in In/Pb codoped SnTe, a 60% improvement over pure SnTe.
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Affiliation(s)
- Wenqi Lu
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
| | - Tiantian He
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
| | - Shuang Li
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
| | - Xinru Zuo
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
| | - Yao Zheng
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
| | - Xunuo Lou
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
| | - Jian Zhang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China
| | - Di Li
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, PR China
| | - Jizi Liu
- Materials Characterization & Research Center, School of Materials Science and Engineering, Nanjing University of Science and Technology, Jiangsu 210094, China.
| | - Guodong Tang
- MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials Technology, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, PR China.
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17
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Sa B, Chen J, Yang X, Yang H, Zheng J, Xu C, Li J, Wu B, Zhan H. Elastic Anisotropy and Optic Isotropy in Black Phosphorene/Transition-Metal Trisulfide van der Waals Heterostructures. ACS OMEGA 2019; 4:4101-4108. [PMID: 31459619 PMCID: PMC6648407 DOI: 10.1021/acsomega.9b00011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/04/2019] [Indexed: 05/31/2023]
Abstract
Anisotropic two-dimensional materials with direction-dependent mechanical and optical properties have attracted significant attention in recent years. In this work, based on density functional theory calculations, unexpected elastic anisotropy and optical isotropy in van der Waals (vdW) heterostructures have been theoretically proposed by assembling the well-known anisotropic black phosphorene (BP) and transition-metal trisulfides MS3 (M = Ti, Hf) together. It is interesting to see that the BP/MS3 vdW heterostructures show anisotropic flexibility in different directions according to the elastic constants, Young's modulus, and Poisson's ratio. We have further unraveled their physical origin of the type-II band structure nature with their conduction band minimum and valence band maximum separated in different layers. In particular, our results on the optical response functions including the excitonic effects of the BP/MS3 vdW heterostructures suggest their unexpected optical isotropies together with the enhancements of the solar energy conversion efficiency.
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Affiliation(s)
- Baisheng Sa
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
| | - Jianhui Chen
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
| | - Xuhui Yang
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
| | - Honglei Yang
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
| | - Jingying Zheng
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
| | - Chao Xu
- Xiamen Talentmats New Materials Science
& Technology Co., Ltd., Xiamen 361015, P. R. China
| | - Junjie Li
- School of Applied Mathematics, Xiamen University
of Technology, Xiamen 361024, P. R. China
| | - Bo Wu
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
| | - Hongbing Zhan
- Key Laboratory of
Eco-materials Advanced Technology, College of Materials Science and
Engineering, Fuzhou University, Fuzhou 350108, P. R. China
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18
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Choi JR, Ju S. Properties of the Geometric Phase in Electromechanical Oscillations of Carbon-Nanotube-Based Nanowire Resonators. NANOSCALE RESEARCH LETTERS 2019; 14:44. [PMID: 30721358 PMCID: PMC6363811 DOI: 10.1186/s11671-019-2855-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
The geometric phase is an extra phase evolution in the wave function of vibrations that is potentially applicable in a broad range of science and technology. The characteristics of the geometric phase in the squeezed state for a carbon-nanotube-based nanowire resonator have been investigated by means of the invariant operator method. The introduction of a linear invariant operator, which is useful for treating a complicated time-dependent Hamiltonian system, enabled us to derive the analytical formula of the geometric phase. By making use of this, we have analyzed the time behavior of the geometric phase based on relevant illustrations. The influence of squeezing parameters on the evolution of the geometric phase has been investigated. The geometric phase, in large, oscillates, and the envelope of such oscillation increases over time. The rate of the increase of the geometric phase is large when the parameters, such as the classical amplitude of the oscillation, the damping factor, and the amplitude of the driving force, are large. We have confirmed a very sharp increase of the geometric phase over time in the case that the angular frequency of the system reaches near the resonance angular frequency. Our development regarding the characteristics of the geometric phase is crucial for understanding the topological features in nanowire oscillations.
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Affiliation(s)
- Jeong Ryeol Choi
- Department of Physics, Kyonggi University, Gwanggyosan-ro, Yeongtong-gu, Suwon, Gyeonggi-do, 16227 Republic of Korea
| | - Sanghyun Ju
- Department of Physics, Kyonggi University, Gwanggyosan-ro, Yeongtong-gu, Suwon, Gyeonggi-do, 16227 Republic of Korea
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19
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Sadowski J, Dziawa P, Kaleta A, Kurowska B, Reszka A, Story T, Kret S. Defect-free SnTe topological crystalline insulator nanowires grown by molecular beam epitaxy on graphene. NANOSCALE 2018; 10:20772-20778. [PMID: 30402641 DOI: 10.1039/c8nr06096g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
SnTe topological crystalline insulator nanowires have been grown by molecular beam epitaxy on graphene/SiC substrates. The nanowires have a cubic rock-salt structure, they grow along the [001] crystallographic direction and have four sidewalls consisting of {100} crystal planes known to host metallic surface states with a Dirac dispersion. Thorough high resolution transmission electron microscopy investigations show that the nanowires grow on graphene in the van der Waals epitaxy mode induced when the catalyzing Au nanoparticles mix with Sn delivered from a SnTe flux, providing a liquid Au-Sn alloy. The nanowires are totally free from structural defects, but their {001} sidewalls are prone to oxidation, which points out the necessity of depositing a protective capping layer in view of exploiting the magneto-electric transport phenomena involving charge carriers occupying topologically protected states.
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Affiliation(s)
- Janusz Sadowski
- Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warszawa, Poland.
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20
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Yang J, Yu W, Pan Z, Yu Q, Yin Q, Guo L, Zhao Y, Sun T, Bao Q, Zhang K. Ultra-Broadband Flexible Photodetector Based on Topological Crystalline Insulator SnTe with High Responsivity. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1802598. [PMID: 30126077 DOI: 10.1002/smll.201802598] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 07/26/2018] [Indexed: 06/08/2023]
Abstract
Topological crystalline insulators (TCIs) are predicted to be a promising candidate material for ultra-broadband photodetectors ranging from ultraviolet (UV) to terahertz (THz) due to its gapless surface state and narrow bulk bandgap. However, the low responsivity of TCIs-based photodetectors limits their further applications. In this regard, a high-performance photodetector based on SnTe, a recently developed TCI, working in a broadband wavelength range from deep UV to mid-IR with high responsivity is reported. By taking advantage of the strong light absorption and small bandgap of SnTe, photodetectors based on the as-grown SnTe crystalline nanoflakes as well as specific short channel length achieve a high responsivity (71.11 A W-1 at 254 nm, 49.03 A W-1 at 635 nm, 10.91 A W-1 at 1550 nm, and 4.17 A W-1 at 4650 nm) and an ultra-broad spectral response (254-4650 nm) simultaneously. Moreover, for the first time, a durable flexible SnTe photodetector fabricated directly on a polyethylene terephthalate film is demonstrated. These results prove the great potential of TCIs as a promising material for integrated and flexible optoelectronic devices.
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Affiliation(s)
- Jie Yang
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei, 230026, Anhui, P. R. China
- Key Lab of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, Jiangsu, P. R. China
| | - Wenzhi Yu
- Department of Materials Science and Engineering, and Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, 3800, Australia
| | - Zhenghui Pan
- Key Lab of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, Jiangsu, P. R. China
| | - Qiang Yu
- Key Lab of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, Jiangsu, P. R. China
| | - Qing Yin
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei, 230026, Anhui, P. R. China
- Key Lab of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, Jiangsu, P. R. China
| | - Lei Guo
- School of Physics, Southeast University, Nanjing, 211189, Jiangsu, P. R. China
| | - Yanfei Zhao
- Key Lab of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, Jiangsu, P. R. China
| | - Tian Sun
- Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, 215123, Jiangsu, P. R. China
| | - Qiaoliang Bao
- Department of Materials Science and Engineering, and Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University, Clayton, Victoria, 3800, Australia
| | - Kai Zhang
- School of Nano Technology and Nano Bionics, University of Science and Technology of China, Hefei, 230026, Anhui, P. R. China
- Key Lab of Nanodevices and Applications, i-Lab, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, 215123, Jiangsu, P. R. China
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21
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Vasylenko A, Marks S, Wynn JM, Medeiros PVC, Ramasse QM, Morris AJ, Sloan J, Quigley D. Electronic Structure Control of Sub-nanometer 1D SnTe via Nanostructuring within Single-Walled Carbon Nanotubes. ACS NANO 2018; 12:6023-6031. [PMID: 29782147 DOI: 10.1021/acsnano.8b02261] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Nanostructuring, e. g., reduction of dimensionality in materials, offers a viable route toward regulation of materials electronic and hence functional properties. Here, we present the extreme case of nanostructuring, exploiting the capillarity of single-walled carbon nanotubes (SWCNTs) for the synthesis of the smallest possible SnTe nanowires with cross sections as thin as a single atom column. We demonstrate that by choosing the appropriate diameter of a template SWCNT, we can manipulate the structure of the quasi-one-dimensional (1D) SnTe to design electronic behavior. From first principles, we predict the structural re-formations that SnTe undergoes in varying encapsulations and confront the prediction with TEM imagery. To further illustrate the control of physical properties by nanostructuring, we study the evolution of transport properties in a homologous series of models of synthesized and isolated SnTe nanowires varying only in morphology and atomic layer thickness. This extreme scaling is predicted to significantly enhance thermoelectric performance of SnTe, offering a prospect for further experimental studies and future applications.
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Affiliation(s)
- Andrij Vasylenko
- Department of Physics , University of Warwick , Coventry , CV4 7AL , United Kingdom
| | - Samuel Marks
- Department of Physics , University of Warwick , Coventry , CV4 7AL , United Kingdom
| | - Jamie M Wynn
- Cavendish Laboratory , University of Cambridge , Cambridge , CB3 0HE , United Kingdom
| | - Paulo V C Medeiros
- Cavendish Laboratory , University of Cambridge , Cambridge , CB3 0HE , United Kingdom
| | - Quentin M Ramasse
- SuperSTEM Laboratory, SciTech Daresbury Campus , Daresbury , WA44AD , United Kingdom
| | - Andrew J Morris
- School of Metallurgy and Materials , University of Birmingham , Birmingham , B15 2TT , United Kingdom
| | - Jeremy Sloan
- Department of Physics , University of Warwick , Coventry , CV4 7AL , United Kingdom
| | - David Quigley
- Department of Physics , University of Warwick , Coventry , CV4 7AL , United Kingdom
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Feng D, Ge ZH, Chen YX, Li J, He J. Hydrothermal synthesis of SnQ (Q = Te, Se, S) and their thermoelectric properties. NANOTECHNOLOGY 2017; 28:455707. [PMID: 29039358 DOI: 10.1088/1361-6528/aa8b29] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Lead-free IV-VI semiconductors SnQ (Q = Te, Se, S) are deemed as promising thermoelectric (TE) materials. In this work, we designed a hydrothermal route to selectively synthesize single phase SnTe, SnSe and SnS nanopowders. For all three samples, the phase structure were characterized by x-ray diffraction, SnTe particles with octahedron structure and SnSe/SnS particles with plate-like shape were observed by field emission scanning electron microscopy and transmission electron microscopy, the formation mechanism was discussed in detail. Then, SnTe, SnSe and SnS nanopowders were densified by spark plasma sintering for investigating TE properties. It was noticed that SnSe and SnS exhibited remarkably anisotropy in both electrical and thermal properties attributed to the layered crystal structure. The highest ZT values 0.79 at 873 K, 0.21 at 773 K, and 0.13 at 773 K were achieved for SnTe, SnSe and SnS bulk samples, respectively.
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Affiliation(s)
- Dan Feng
- State Key Laboratory for Mechanical Behavior of Materials and Frontier Institute of Science and Technology, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China. Shenzhen Key Laboratory of Thermoelectric Materials, Department of physics, South University of Science and Technology of China, Shenzhen 518055, People's Republic of China
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23
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Li Z, Xu E, Losovyj Y, Li N, Chen A, Swartzentruber B, Sinitsyn N, Yoo J, Jia Q, Zhang S. Surface oxidation and thermoelectric properties of indium-doped tin telluride nanowires. NANOSCALE 2017; 9:13014-13024. [PMID: 28832046 DOI: 10.1039/c7nr04934j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The recent discovery of excellent thermoelectric properties and topological surface states in SnTe-based compounds has attracted extensive attention in various research areas. Indium doped SnTe is of particular interest because, depending on the doping level, it can either generate resonant states in the bulk valence band leading to enhanced thermoelectric properties, or induce superconductivity that coexists with topological states. Here we report on the vapor deposition of In-doped SnTe nanowires and the study of their surface oxidation and thermoelectric properties. The nanowire growth is assisted by Au catalysts, and their morphologies vary as a function of substrate position and temperature. Transmission electron microscopy characterization reveals the formation of an amorphous surface in single crystalline nanowires. X-ray photoelectron spectroscopy studies suggest that the nanowire surface is composed of In2O3, SnO2, Te and TeO2 which can be readily removed by argon ion sputtering. Exposure of the cleaned nanowires to atmosphere leads to rapid oxidation of the surface within only one minute. Characterization of electrical conductivity σ, thermopower S, and thermal conductivity κ was performed on the same In-doped nanowire which shows suppressed σ and κ but enhanced S yielding an improved thermoelectric figure of merit ZT compared to the undoped SnTe.
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Affiliation(s)
- Zhen Li
- Department of Physics, Indiana University, Bloomington, IN 47405, USA.
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24
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Evidence of robust 2D transport and Efros-Shklovskii variable range hopping in disordered topological insulator (Bi 2Se 3) nanowires. Sci Rep 2017; 7:7825. [PMID: 28798385 PMCID: PMC5552836 DOI: 10.1038/s41598-017-08018-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 07/03/2017] [Indexed: 11/08/2022] Open
Abstract
We report the experimental observation of variable range hopping conduction in focused-ion-beam (FIB) fabricated ultra-narrow nanowires of topological insulator (Bi2Se3). The value of the exponent (d + 1)-1 in the hopping equation was extracted as [Formula: see text]for different widths of nanowires, which is the proof of the presence of Efros-Shklovskii hopping transport mechanism in a strongly disordered system. High localization lengths (0.5 nm, 20 nm) were calculated for the devices. A careful analysis of the temperature dependent fluctuations present in the magnetoresistance curves, using the standard Universal Conductance Fluctuation theory, indicates the presence of 2D topological surface states. Also, the surface state contribution to the conductance was found very close to one conductance quantum. We believe that our experimental findings shed light on the understanding of quantum transport in disordered topological insulator based nanostructures.
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25
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Zhang H, Man B, Zhang Q. Topological Crystalline Insulator SnTe/Si Vertical Heterostructure Photodetectors for High-Performance Near-Infrared Detection. ACS APPLIED MATERIALS & INTERFACES 2017; 9:14067-14077. [PMID: 28398029 DOI: 10.1021/acsami.7b01098] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Due to the gapless surface state and narrow bulk band gap, the light absorption of topological crystalline insulators covers a broad spectrum ranging from terahertz to infrared, revealing promising applications in new generation optoelectronic devices. To date, the photodetectors based on topological insulators generally suffer from a large dark current and a weaker photocurrent especially under the near-infrared lights, which severely limits the practical application of devices. Owing to the lower excitation energy of infrared lights, the photodetection application of topological crystalline insulators in the near-infrared region relies critically on understanding the preparation and properties of their heterostructures. Herein, we fabricate the high-quality topological crystalline insulator SnTe film/Si vertical heterostructure by a simple physical vapor deposition process. The resultant heterostructure exhibits an excellent diode characteristic, enabling the construction of high-performance near-infrared photodetectors. The built-in electric field at SnTe/Si interface enhances the absorption efficiency of near-infrared lights and greatly facilitates the separation of photogenerated carriers, making the device capable of operating as a self-driven photodetector. The as-grown SnTe film acts as the hole transport layer in heterostructure photodetectors, promoting the transport of holes to electrode and reducing electron-hole recombination effectively. These merits enable the SnTe/Si heterostructure photodetector to have a high responsivity of 2.36 AW-1, a high detectivity of 1.54 × 1014 Jones, and a large bandwidth of 104 Hz in the near-infrared wavelength, which makes the detector have a promising market in novel device applications.
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Affiliation(s)
- Hongbin Zhang
- School of Physics and Electronics, Shandong Normal University , Jinan, Shandong 250014, P. R. China
| | - Baoyuan Man
- School of Physics and Electronics, Shandong Normal University , Jinan, Shandong 250014, P. R. China
| | - Qi Zhang
- School for Radiological and Interdisciplinary Sciences (RAD-X) and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Medical College of Soochow University , Suzhou, Jiangsu 215123, P. R. China
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26
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Bhattacharyya B, Sharma A, Awana VPS, Srivastava AK, Senguttuvan TD, Husale S. Observation of quantum oscillations in FIB fabricated nanowires of topological insulator (Bi 2Se 3). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:115602. [PMID: 28170351 DOI: 10.1088/1361-648x/aa5536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
In the last few years, research based on topological insulators (TIs) has been of great interest due to their intrinsic exotic fundamental properties and potential applications such as quantum computers or spintronics. The fabrication of TI nanodevices and the study of their transport properties has mostly focused on high quality crystalline nanowires or nanoribbons. Here, we report a robust approach to Bi2Se3 nanowire formation from deposited flakes using an ion beam milling method. Fabricated Bi2Se3 nanowire devices were employed to investigate the robustness of the topological surface state (TSS) to gallium ion doping and any deformation in the material due to the fabrication tools. We report on the quantum oscillations in magnetoresistance (MR) curves under the parallel magnetic field. The resistance versus magnetic field curves are studied and compared with Aharonov-Bohm (AB) interference effects, which further demonstrate transport through the TSS. The fabrication route and observed electronic transport properties indicate clear quantum oscillations, and these can be exploited further in studying the exotic electronic properties associated with TI-based nanodevices.
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Affiliation(s)
- Biplab Bhattacharyya
- Academy of Scientific and Innovative Research (AcSIR), National Physical Laboratory, Council of Scientific and Industrial Research, Dr K S Krishnan Road, New Delhi 110012, India. National Physical Laboratory, Council of Scientific and Industrial Research, Dr K S Krishnan Road, New Delhi 110012, India
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27
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Unexpected Au Alloying in Tailoring In-Doped SnTe Nanostructures with Gold Nanoparticles. CRYSTALS 2017. [DOI: 10.3390/cryst7030078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Bhattacharyya B, Sharma A, Awana VPS, Senguttuvan TD, Husale S. FIB synthesis of Bi 2Se 3 1D nanowires demonstrating the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:07LT01. [PMID: 28035087 DOI: 10.1088/1361-648x/29/7/07lt01] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Since the discovery of topological insulators (TIs), there are considerable interests in demonstrating metallic surface states (SS), their shielded robust nature to the backscattering and study their properties at nanoscale dimensions by fabricating nanodevices. Here we address an important scientific issue related to TI whether one can clearly demonstrate the robustness of topological surface states (TSS) to the presence of disorder that does not break any fundamental symmetry. The simple straightforward method of FIB milling was used to synthesize nanowires of Bi2Se3 which we believe is an interesting route to test robustness of TSS and the obtained results are new compared to many of the earlier papers on quantum transport in TI demonstrating the robustness of metallic SS to gallium (Ga) doping. In the presence of perpendicular magnetic field, we have observed the co-existence of Shubnikov-de Haas oscillations and linear magnetoresistance (LMR), which was systematically investigated for different channel lengths, indicating the Dirac dispersive surface states. The transport properties and estimated physical parameters shown here demonstrate the robustness of SS to the fabrication tools triggering flexibility to explore new exotic quantum phenomena at nanodevice level.
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Affiliation(s)
- Biplab Bhattacharyya
- Academy of Scientific and Innovative Research (AcSIR), National Physical Laboratory, Council of Scientific and Industrial Research, Dr K S Krishnan Road, New Delhi 110012, India. National Physical Laboratory, Council of Scientific and Industrial Research, Dr K S Krishnan Road, New Delhi 110012, India
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29
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Zou YC, Chen ZG, Kong F, Zhang E, Drennan J, Cho K, Xiu F, Zou J. Surface-energy engineered Bi-doped SnTe nanoribbons with weak antilocalization effect and linear magnetoresistance. NANOSCALE 2016; 8:19383-19389. [PMID: 27845804 DOI: 10.1039/c6nr07140f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The rational design of semiconductor nanocrystals with well-defined surfaces is a crucial step towards the realization of next-generation photodetectors, and thermoelectric and spintronic devices. SnTe nanocrystals, as an example, are particularly attractive as a type of topological crystalline insulator, where surface facets determine their surface states. However, most of the available SnTe nanocrystals are dominated by thermodynamically stable {100} facets, and it is challenging to grow uniform nanocrystals with {111} facets. In this study, guided by surface-energy calculations, we employ a chemical vapour deposition approach to fabricate Bi doped SnTe nanostructures, in which their surface facets are tuned by Bi doping. The obtained Bi doped SnTe nanoribbons with distinct {111} surfaces show a weak antilocalization effect and linear magnetoresistance under high magnetic fields, which demonstrate their great potential for future spintronic applications.
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Affiliation(s)
- Yi-Chao Zou
- Materials Engineering, University of Queensland, Brisbane, QLD 4072, Australia.
| | - Zhi-Gang Chen
- Materials Engineering, University of Queensland, Brisbane, QLD 4072, Australia. and Centre for Future Materials, University of Southern Queensland, Springfield, QLD 4300, Australia
| | - Fantai Kong
- Department of Materials Science & Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Enze Zhang
- Key Laboratory of Surface Physics and Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - John Drennan
- Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD 4072, Australia
| | - Kyeongjae Cho
- Department of Materials Science & Engineering, The University of Texas at Dallas, Richardson, TX 75080, USA
| | - Faxian Xiu
- Key Laboratory of Surface Physics and Department of Physics, and Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Jin Zou
- Materials Engineering, University of Queensland, Brisbane, QLD 4072, Australia. and Centre for Microscopy and Microanalysis, University of Queensland, Brisbane, QLD 4072, Australia
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30
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Gooth J, Zierold R, Sergelius P, Hamdou B, Garcia J, Damm C, Rellinghaus B, Pettersson HJ, Pertsova A, Canali C, Borg M, Nielsch K. Local Magnetic Suppression of Topological Surface States in Bi2Te3 Nanowires. ACS NANO 2016; 10:7180-7188. [PMID: 27351276 DOI: 10.1021/acsnano.6b03537] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Locally induced, magnetic order on the surface of a topological insulator nanowire could enable room-temperature topological quantum devices. Here we report on the realization of selective magnetic control over topological surface states on a single facet of a rectangular Bi2Te3 nanowire via a magnetic insulating Fe3O4 substrate. Low-temperature magnetotransport studies provide evidence for local time-reversal symmetry breaking and for enhanced gapping of the interfacial 1D energy spectrum by perpendicular magnetic-field components, leaving the remaining nanowire facets unaffected. Our results open up great opportunities for development of dissipation-less electronics and spintronics.
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Affiliation(s)
- Johannes Gooth
- Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11 B, 20355 Hamburg, Germany
- IBM Research-Zurich , Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Robert Zierold
- Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11 B, 20355 Hamburg, Germany
| | - Philip Sergelius
- Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11 B, 20355 Hamburg, Germany
| | - Bacel Hamdou
- Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11 B, 20355 Hamburg, Germany
| | - Javier Garcia
- Institute for Metallic Materials, IFW Dresden , Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Christine Damm
- Institute for Metallic Materials, IFW Dresden , Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Bernd Rellinghaus
- Institute for Metallic Materials, IFW Dresden , Helmholtzstrasse 20, 01069 Dresden, Germany
| | - Håkan Jan Pettersson
- Division of Solid State Physics and NanoLund, Lund University , Box 118, 22100 Lund, Sweden
- Center for Applied Mathematics and Physics, Halmstad University , Box 823, 30118 Halmstad, Sweden
| | - Anna Pertsova
- Department of Physics and Electrical Engineering, Linnaeus University , 39182 Kalmar, Sweden
| | - Carlo Canali
- Department of Physics and Electrical Engineering, Linnaeus University , 39182 Kalmar, Sweden
| | - Mattias Borg
- IBM Research-Zurich , Säumerstrasse 4, 8803 Rüschlikon, Switzerland
| | - Kornelius Nielsch
- Institute of Nanostructure and Solid State Physics, Universität Hamburg , Jungiusstrasse 11 B, 20355 Hamburg, Germany
- Institute for Metallic Materials, IFW Dresden , Helmholtzstrasse 20, 01069 Dresden, Germany
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31
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Wang Q, Cai K, Li J, Huang Y, Wang Z, Xu K, Wang F, Zhan X, Wang F, Wang K, He J. Rational Design of Ultralarge Pb1-x Snx Te Nanoplates for Exploring Crystalline Symmetry-Protected Topological Transport. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2016; 28:617-623. [PMID: 26618500 DOI: 10.1002/adma.201504630] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Revised: 10/19/2015] [Indexed: 06/05/2023]
Abstract
Ultralarge topological crystalline insulator Pb1-x Snx Te nanoplates are developed by controlling substrate surface chemical properties in a cost-efficient chemical vapor deposition (CVD) process. Dominant topological surface transport is demonstrated by a gate-voltage-controlled weak (anti)localization effect, indicating the potential application of these nanoplates to low-dissipation topological transistors.
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Affiliation(s)
- Qisheng Wang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kaiming Cai
- SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, 100083, P. R. China
| | - Jie Li
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Yun Huang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Zhenxing Wang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kai Xu
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Feng Wang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Xueying Zhan
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Fengmei Wang
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Kaiyou Wang
- SKLSM, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing, 100083, P. R. China
| | - Jun He
- CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
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32
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Yan Y, Zhou X, Jin H, Li CZ, Ke X, Van Tendeloo G, Liu K, Yu D, Dressel M, Liao ZM. Surface-Facet-Dependent Phonon Deformation Potential in Individual Strained Topological Insulator Bi2Se3 Nanoribbons. ACS NANO 2015; 9:10244-51. [PMID: 26365014 DOI: 10.1021/acsnano.5b04057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Strain is an important method to tune the properties of topological insulators. For example, compressive strain can induce superconductivity in Bi2Se3 bulk material. Topological insulator nanostructures are the superior candidates to utilize the unique surface states due to the large surface to volume ratio. Therefore, it is highly desirable to monitor the local strain effects in individual topological insulator nanostructures. Here, we report the systematical micro-Raman spectra of single strained Bi2Se3 nanoribbons with different thicknesses and different surface facets, where four optical modes are resolved in both Stokes and anti-Stokes Raman spectral lines. A striking anisotropy of the strain dependence is observed in the phonon frequency of strained Bi2Se3 nanoribbons grown along the ⟨112̅0⟩ direction. The frequencies of the in-plane Eg(2) and out-of-plane A1g(1) modes exhibit a nearly linear blue-shift against bending strain when the nanoribbon is bent along the ⟨112̅0⟩ direction with the curved {0001} surface. In this case, the phonon deformation potential of the Eg(2) phonon for 100 nm-thick Bi2Se3 nanoribbon is up to 0.94 cm(–1)/%, which is twice of that in Bi2Se3 bulk material (0.52 cm(–1)/%). Our results may be valuable for the strain modulation of individual topological insulator nanostructures.
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Affiliation(s)
- Yuan Yan
- Physikalisches Institut, Universität Stuttgart , 70550 Stuttgart, Germany
| | - Xu Zhou
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , 100871 Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University , 100871 Beijing, China
| | - Han Jin
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , 100871 Beijing, China
| | - Cai-Zhen Li
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , 100871 Beijing, China
| | - Xiaoxing Ke
- EMAT (Electron Microscopy for Materials Science), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - Gustaaf Van Tendeloo
- EMAT (Electron Microscopy for Materials Science), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , 100871 Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University , 100871 Beijing, China
- Collaborative Innovation Center of Quantum Matter , Beijing, China
| | - Dapeng Yu
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , 100871 Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University , 100871 Beijing, China
- Collaborative Innovation Center of Quantum Matter , Beijing, China
| | - Martin Dressel
- Physikalisches Institut, Universität Stuttgart , 70550 Stuttgart, Germany
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University , 100871 Beijing, China
- Collaborative Innovation Center of Quantum Matter , Beijing, China
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Wang Q, Wang F, Li J, Wang Z, Zhan X, He J. Low-Dimensional Topological Crystalline Insulators. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:4613-4624. [PMID: 26174151 DOI: 10.1002/smll.201501381] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 06/16/2015] [Indexed: 06/04/2023]
Abstract
Topological crystalline insulators (TCIs) are recently discovered topological phase with robust surface states residing on high-symmetry crystal surfaces. Different from conventional topological insulators (TIs), protection of surface states on TCIs comes from point-group symmetry instead of time-reversal symmetry in TIs. The distinct properties of TCIs make them promising candidates for the use in novel spintronics, low-dissipation quantum computation, tunable pressure sensor, mid-infrared detector, and thermoelectric conversion. However, similar to the situation in TIs, the surface states are always suppressed by bulk carriers, impeding the exploitation of topology-induced quantum phenomenon. One effective way to solve this problem is to grow low-dimensional TCIs which possess large surface-to-volume ratio, and thus profoundly increase the carrier contribution from topological surface states. Indeed, through persistent effort, researchers have obtained unique quantum transport phenomenon, originating from topological surface states, based on controllable growth of low-dimensional TCIs. This article gives a comprehensive review on the recent progress of controllable synthesis and topological surface transport of low-dimensional TCIs. The possible future direction about low-dimensional TCIs is also briefly discussed at the end of this paper.
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Affiliation(s)
- Qisheng Wang
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Feng Wang
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Jie Li
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Zhenxing Wang
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Xueying Zhan
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
| | - Jun He
- National Center for Nanoscience and Technology, Beijing, 100190, P. R. China
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Guo Y, Liu Z, Peng H. A Roadmap for Controlled Production of Topological Insulator Nanostructures and Thin Films. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:3290-3305. [PMID: 25727694 DOI: 10.1002/smll.201403426] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Revised: 01/14/2015] [Indexed: 06/04/2023]
Abstract
The group V-VI chalcogenide semiconductors (Bi2 Se3 , Bi2 Te3 , and Sb2 Te3 ) have long been known as thermoelectric materials. Recently, they have been once more generating interest because Bi2 Se3 , Bi2 Te3 and Sb2 Te3 have been crowned as 3D topological insulators (TIs), which have insulating bulk gaps and metallic Dirac surface states. One big challenge in the study of TIs is the lack of high-quality materials with few defects and insulating bulk states. To manifest the topological surface states, it is critical to suppress the contribution from the bulk carriers. Controlled production of TI nanostructures that have a large surface-to-volume ratio is an efficient way to reduce the bulk conductance and to significantly enhance the topological surface conduction. In this review article, the recent progress on the preparation of TI nanostructures is highlighted. Basic production methods for TI nanostructures are introduced in detail. Furthermore, several specific production approaches to reduce the residual bulk carriers from defects are summarized. Finally, the progress and the prospects of the production of TI-based heterostructures, which hold promise in both fundamental study and novel applications are discussed.
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Affiliation(s)
- Yunfan Guo
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P.R. China
| | - Zhongfan Liu
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P.R. China
| | - Hailin Peng
- Center for Nanochemistry, Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, P.R. China
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35
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Detection of highly conductive surface electron states in topological crystalline insulators Pb(1-x)SnxSe using laser terahertz radiation. Sci Rep 2015; 5:11540. [PMID: 26096529 PMCID: PMC4476126 DOI: 10.1038/srep11540] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 05/19/2015] [Indexed: 11/08/2022] Open
Abstract
We suggest a method for detection of highly conductive surface electron states including topological ones. The method is based on measurements of the photoelectromagnetic effect using terahertz laser pulses. In contrast to conventional transport measurements, the method is not sensitive to the bulk conductivity. The method is demonstrated on an example of topological crystalline insulators Pb(1-x)SnxSe. It is shown that highly conductive surface electron states are present in Pb(1-x)SnxSe both in the inverse and direct electron energy spectrum.
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36
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Wang Q, Safdar M, Wang Z, Zhan X, Xu K, Wang F, He J. Topological Crystalline Insulator Pb1-x Snx Se Nanowires with {100} Facets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:2019-2025. [PMID: 25521417 DOI: 10.1002/smll.201403159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2014] [Revised: 11/10/2014] [Indexed: 06/04/2023]
Abstract
Surface states properties of topological crystalline insulator Pb1-x Snx Se are strongly dependent on crystallographic plane orientation. Rectangular prismatic Pbx Sn1-x Se nanowires and nanoplates are grown with distinct {100} surfaces on mica sheets. Substrate surface chemical properties are found to be the critical factors that affect the vapor deposition process and final shapes of Pb1-x Snx Se nanostructures.
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Affiliation(s)
- Qisheng Wang
- National Center for Nanscience and Technology, Beijing, China
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Safdar M, Wang Q, Wang Z, Zhan X, Xu K, Wang F, Mirza M, He J. Weak antilocalization effect of topological crystalline insulator Pb(1-x)Sn(x)Te nanowires with tunable composition and distinct {100} facets. NANO LETTERS 2015; 15:2485-2490. [PMID: 25730475 DOI: 10.1021/nl504976g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Pb(1-x)Sn(x)Te is a unique topological crystalline insulator (TCI) that undergoes a topological phase transition from topological trivial insulator to TCI with the change of Sn content and temperature. Meanwhile, the surface states properties of Pb(1-x)Sn(x)Te are strongly dependent on crystallographic plane orientation. In this work, we first reported controllable synthesis of rectangular prismatic Pb(x)Sn(1-x)Te nanowires by vapor deposition method. Rectangular prismatic Pb(x)Sn(1-x)Te nanowires exhibits distinct {100} surfaces. Furthermore, The Sn composition of Pb(1-x)Sn(x)Te nanowires can be continuously controlled from 0 to 1. Low temperature magnetotransport shows that PbTe nanowire exhibits weak localization (WL) effect, whereas Pb0.5Sn0.5Te and Pb0.2Sn0.8Te nanowires display pronounced weak antilocalization (WAL) effect. This transition is explained by the topological phase transform of Pb(1-x)Sn(x)Te from trivial to nontrivial insulator with Sn content (x) exceeding 0.38. Pb(x)Sn(1-x)Te nanowires synthesized in this work lay a foundation for probing spin-correlated electron transport and show great potentials for future applications of tunable spintronic devices.
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Affiliation(s)
- Muhammad Safdar
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Qisheng Wang
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Zhenxing Wang
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Xueying Zhan
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Kai Xu
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Fengmei Wang
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Misbah Mirza
- National Center for Nanoscience and Technology, Beijing 100190, China
| | - Jun He
- National Center for Nanoscience and Technology, Beijing 100190, China
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Liu J, Qian X, Fu L. Crystal field effect induced topological crystalline insulators in monolayer IV-VI semiconductors. NANO LETTERS 2015; 15:2657-2661. [PMID: 25741907 DOI: 10.1021/acs.nanolett.5b00308] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Two-dimensional (2D) topological crystalline insulators (TCIs) were recently predicted in thin films of the SnTe class of IV-VI semiconductors, which can host metallic edge states protected by mirror symmetry. As thickness decreases, quantum confinement effect will increase and surpass the inverted gap below a critical thickness, turning TCIs into normal insulators. Surprisingly, based on first-principles calculations, here we demonstrate that (001) monolayers of rocksalt IV-VI semiconductors XY (X = Ge, Sn, Pb and Y = S, Se, Te) are 2D TCIs with the fundamental band gap as large as 260 meV in monolayer PbTe. This unexpected nontrivial topological phase stems from the strong crystal field effect in the monolayer, which lifts the degeneracy between p(x,y) and p(z) orbitals and leads to band inversion between cation pz and anion px,y orbitals. This crystal field effect induced topological phase offers a new strategy to find and design other atomically thin 2D topological materials.
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Affiliation(s)
- Junwei Liu
- †Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | | | - Liang Fu
- †Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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Sulaev A, Zeng M, Shen SQ, Cho SK, Zhu WG, Feng YP, Eremeev SV, Kawazoe Y, Shen L, Wang L. Electrically tunable in-plane anisotropic magnetoresistance in topological insulator BiSbTeSe2 nanodevices. NANO LETTERS 2015; 15:2061-2066. [PMID: 25665017 DOI: 10.1021/nl504956s] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We report tunable in-plane anisotropic magnetoresistance (AMR) in nanodevices based on topological insulator BiSbTeSe2 (BSTS) nanoflakes by electric gating. The AMR can be changed continuously from negative to positive when the Fermi level is manipulated to cross the Dirac point by an applied gate electric field. We also discuss effects of the gate electric field, current density, and magnetic field on the in-plane AMR with a simple physical model, which is based on the in-plane magnetic field induced shift of the spin-momentum locked topological two surface states that are coupled through side surfaces and bulk weak antilocalization (WAL). The large, tunable and bipolar in-plane AMR in BSTS devices provides the possibility of fabricating more sensitive logic and magnetic random access memory AMR devices.
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Affiliation(s)
- Azat Sulaev
- School of Physical and Mathematical Sciences, Division of Physics and Applied Physics, Nanyang Technological University , Singapore 637371
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40
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Zhang C, Liu Y, Yuan X, Wang W, Liang S, Xiu F. Highly tunable Berry phase and ambipolar field effect in topological crystalline insulator Pb(1-x)Sn(x)Se. NANO LETTERS 2015; 15:2161-2167. [PMID: 25705997 DOI: 10.1021/acs.nanolett.5b00172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Recently, rock-salt IV-VI semiconductors, such as Pb(1-x)Sn(x)Se(Te) and SnTe, have been observed to host topological crystalline insulator (TCI) states. The nontrivial states have long been believed to exhibit ambipolar field effects and possess massive Dirac Fermions in two-dimension (2D) limit due to the surface hybridization. However, these exciting attributes of TCI remain previously inaccessible owing to the complicated control over composition and thickness. Here, we systematically investigate doping and thickness-induced topological phase transitions by electrical transport. We demonstrate the first evidence of the ambipolar properties in Pb(1-x)Sn(x)Se thin films. Surface gap opening is observed in 10 nm TCI originated from the strong finite-size effect. Importantly, magnetoconductance hosts a competition between weak antilocalization and weak localization, suggesting a strikingly tunable Berry phase evolution and strong electron-electron interaction. Our findings serve as a new probe to study electron behavior and pave the way for further exploring and manipulating this novel 2D TCI phase.
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Affiliation(s)
- Cheng Zhang
- State Key Laboratory of Surface Physics and Department of Physics and ‡Collaborative Innovation Center of Advanced Microstructures, Fudan University , Shanghai 200433, China
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41
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Xu EZ, Li Z, Martinez JA, Sinitsyn N, Htoon H, Li N, Swartzentruber B, Hollingsworth JA, Wang J, Zhang SX. Diameter dependent thermoelectric properties of individual SnTe nanowires. NANOSCALE 2015; 7:2869-2876. [PMID: 25623253 DOI: 10.1039/c4nr05870d] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The lead-free compound tin telluride (SnTe) has recently been suggested to be a promising thermoelectric material. In this work, we report on the first thermoelectric study of individual single-crystalline SnTe nanowires with different diameters ranging from ∼218 to ∼913 nm. Measurements of thermopower S, electrical conductivity σ and thermal conductivity κ were carried out on the same nanowires over a temperature range of 25-300 K. While the electrical conductivity does not show a strong diameter dependence, the thermopower increases by a factor of two when the nanowire diameter is decreased from ∼913 nm to ∼218 nm. The thermal conductivity of the measured NWs is lower than that of the bulk SnTe, which may arise from the enhanced phonon - surface boundary scattering and phonon-defect scattering. Temperature dependent figure of merit ZT was determined for individual nanowires and the achieved maximum value at room temperature is about three times higher than that in bulk samples of comparable carrier density.
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Affiliation(s)
- E Z Xu
- Department of Physics, Indiana University, Bloomington, Indiana 47405, USA.
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42
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Zhou Q, Wang J, Chwee TS, Wu G, Wang X, Ye Q, Xu J, Yang SW. Topological insulators based on 2D shape-persistent organic ligand complexes. NANOSCALE 2015; 7:727-735. [PMID: 25429668 DOI: 10.1039/c4nr05247a] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Topological insulators (TIs) represent an exciting new class of materials with potential applications in spintronics and quantum computing. In this work, we present a theoretical study on a new family of two dimensional (2D) nanomaterials based on the coordination of shape persistent organic ligands (SPOLs) to heavy transition metal ions such as Pd(2+) and Pt(2+). These 2D structures may be readily fabricated and are expected to be stable under normal atmospheric conditions. From first principles calculations and tight-binding model simulations carried out to characterize the bulk band structures, edge states, spin Chern numbers, and the Z2 topological invariants, we were able to identify candidates with non-trivial topological properties that may serve as topological insulators in real world applications.
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Affiliation(s)
- Qionghua Zhou
- Department of Physics, Southeast University, Nanjing 211189, P. R. China.
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43
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Xue X, Zhou Z, Peng B, Zhu MM, Zhang YJ, Ren W, Ye ZG, Chen X, Liu M. Review on nanomaterials synthesized by vapor transport method: growth and their related applications. RSC Adv 2015. [DOI: 10.1039/c5ra13349a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Nanostructures with different dimensions, including bulk crystals, thin films, nanowires, nanobelts and nanorods, have received considerable attention due to their novel functionalities and outstanding applications in various areas.
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Affiliation(s)
- X. Xue
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
| | - Z. Zhou
- Energy Systems Division
- Argonne National Laboratory
- Lemont, USA
| | - B. Peng
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
| | - M. M. Zhu
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
| | - Y. J. Zhang
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
| | - W. Ren
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
| | - Z. G. Ye
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
| | - X. Chen
- Energy Systems Division
- Argonne National Laboratory
- Lemont, USA
| | - M. Liu
- Electronic Materials Research Laboratory
- Key Laboratory of the Ministry of Education & International Center for Dielectric Research
- Xi'an Jiaotong University
- Xi'an 710049, China
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Akiyama R, Fujisawa K, Sakurai R, Kuroda S. Weak antilocalization in (111) thin films of a topological crystalline insulator SnTe. ACTA ACUST UNITED AC 2014. [DOI: 10.1088/1742-6596/568/5/052001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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45
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Shen J, Cha JJ. Topological crystalline insulator nanostructures. NANOSCALE 2014; 6:14133-14140. [PMID: 25350386 DOI: 10.1039/c4nr05124f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Topological crystalline insulators are topological insulators whose surface states are protected by the crystalline symmetry, instead of the time reversal symmetry. Similar to the first generation of three-dimensional topological insulators such as Bi₂Se₃ and Bi₂Te₃, topological crystalline insulators also possess surface states with exotic electronic properties such as spin-momentum locking and Dirac dispersion. Experimentally verified topological crystalline insulators to date are SnTe, Pb₁-xSnxSe, and Pb₁-xSnxTe. Because topological protection comes from the crystal symmetry, magnetic impurities or in-plane magnetic fields are not expected to open a gap in the surface states in topological crystalline insulators. Additionally, because they have a cubic structure instead of a layered structure, branched structures or strong coupling with other materials for large proximity effects are possible, which are difficult with layered Bi₂Se₃ and Bi₂Te₃. Thus, additional fundamental phenomena inaccessible in three-dimensional topological insulators can be pursued. In this review, topological crystalline insulator SnTe nanostructures will be discussed. For comparison, experimental results based on SnTe thin films will be covered. Surface state properties of topological crystalline insulators will be discussed briefly.
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Affiliation(s)
- Jie Shen
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, USA.
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Zhou M, Gibbs ZM, Wang H, Han Y, Xin C, Li L, Snyder GJ. Optimization of thermoelectric efficiency in SnTe: the case for the light band. Phys Chem Chem Phys 2014; 16:20741-8. [PMID: 25162449 DOI: 10.1039/c4cp02091j] [Citation(s) in RCA: 197] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
p-Type PbTe is an outstanding high temperature thermoelectric material with zT of 2 at high temperatures due to its complex band structure which leads to high valley degeneracy. Lead-free SnTe has a similar electronic band structure, which suggests that it may also be a good thermoelectric material. However, stoichiometric SnTe is a strongly p-type semiconductor with a carrier concentration of about 1 × 10(20) cm(-3), which corresponds to a minimum Seebeck coefficient and zT. While in the case of p-PbTe (and n-type La3Te4) one would normally achieve higher zT by using high carrier density in order to populate the secondary band with higher valley degeneracy, SnTe behaves differently. It has a very light, upper valence band which is shown in this work to provide higher zT than doping towards the heavier second band. Therefore, decreasing the hole concentration to maximize the performance of the light band results in higher zT than doping into the high degeneracy heavy band. Here we tune the electrical transport properties of SnTe by decreasing the carrier concentration with iodine doping, and increasing the carrier concentration with Gd doping or by making the samples Te deficient. A peak zT value of 0.6 at 700 K was obtained for SnTe0.985I0.015 which optimizes the light, upper valence band, which is about 50% higher than the other peak zT value of 0.4 for GdzSn1-zTe and SnTe1+y which utilize the high valley degeneracy secondary valence band.
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Affiliation(s)
- Min Zhou
- Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
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47
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Xu K, Wang F, Wang Z, Zhan X, Wang Q, Cheng Z, Safdar M, He J. Component-controllable WS(2(1-x))Se(2x) nanotubes for efficient hydrogen evolution reaction. ACS NANO 2014; 8:8468-76. [PMID: 25110810 DOI: 10.1021/nn503027k] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Owing to the excellent potential for fundamental research and technical applications in optoelectronic devices and catalytic activity for hydrogen evolution reaction (HER), transition metal dichalcogenides have recently attracted much attention. Transition metal sulfide nanostructures have been reported and demonstrated promising application in transistors and photodetectors. However, the growth of transition metal selenide nanostructures and their applications has still been a challenge. In this work, we successfully synthesized high-quality WSe2 nanotubes on carbon fibers via selenization. More importantly, through optimizing the growth conditions, ternary WS2(1–x)Se2x nanotubes were synthesized and the composition of S and Se can be systematically controlled. The as-grown WS2(1–x)Se2x nanotubes on carbon fibers, assembled as a working electrode, revealing low overpotential, high exchange current density, and small series resistance, exhibit excellent electrocatalytic properties for hydrogen evolution reaction. Our study provides the experimental groundwork for the synthesis of low-dimensional transition metal dichalcogenides and may open up exciting opportunities for their application in electronics, photoelectronics, and catalytic electrochemical reactions.
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48
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Shen J, Jung Y, Disa AS, Walker FJ, Ahn CH, Cha JJ. Synthesis of SnTe nanoplates with {100} and {111} surfaces. NANO LETTERS 2014; 14:4183-8. [PMID: 24910959 DOI: 10.1021/nl501953s] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
SnTe is a topological crystalline insulator that possesses spin-polarized, Dirac-dispersive surface states protected by crystal symmetry. Multiple surface states exist on the {100}, {110}, and {111} surfaces of SnTe, with the band structure of surface states depending on the mirror symmetry of a particular surface. Thus, to access surface states selectively, it is critical to control the morphology of SnTe such that only desired crystallographic surfaces are present. Here, we grow SnTe nanostructures using vapor-liquid-solid and vapor-solid growth mechanisms. Previously, SnTe nanowires and nanocrystals have been grown [Saghir et al. Cryst. Growth Des. 2014, 14, 2009-2013; Safdar et al. Cryst. Growth Des. 2014, 14, 2502-2509; Safdar et al. Nano Lett. 2013, 13, 5344-5349; Li et al. Nano Lett. 2013, 13, 5443-5448]. In this report, we demonstrate the synthesis of SnTe nanoplates with lateral dimensions spanning tens of micrometers and thicknesses of a few hundred nanometers. The top and bottom surfaces are either (100) or (111), maximizing topological surface states on these surfaces. Magnetotransport on these SnTe nanoplates shows a high bulk carrier density, consistent with bulk SnTe crystals arising due to defects such as Sn vacancies. In addition, we observe a structural phase transition in these nanoplates from the high-temperature rock salt to a low-temperature rhombohedral structure. For nanoplates with a very high carrier density, we observe a slight upturn in resistance at low temperatures, indicating electron-electron interactions.
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Affiliation(s)
- Jie Shen
- Department of Mechanical Engineering and Materials Science and ‡Department of Applied Physics, Yale University , New Haven, Connecticut 06511, United States
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