1
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Arslanov TR, Zalibekov UZ, Ashurov GG, Losanov KK, Zhao X, Dai B, Ril AI. Ratio of 4:1 between ZnGeAs 2and MnAs phases in a single composite and its impact on the structure-driven magnetoresistance. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:315802. [PMID: 38657635 DOI: 10.1088/1361-648x/ad42f5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/24/2024] [Indexed: 04/26/2024]
Abstract
A strong influence of the lattice degree of freedom on magnetoresistance (MR) under high pressure underlies the conception of 'structure-driven' magnetoresistance (SDMR). In most magnetic or topological materials, the suppression of MR with increasing pressure is a general trend, while for some magnetic composites the MR enhances and even shows unusual behavior as a consequence of structural transition. Here we investigated the SDMR in the composite material based on the ZnGeAs2semiconductor matrix and MnAs magnetic inclusions in a phase ratio of 4:1. At ambient pressure, its magnetic and transport properties are governed by MnAs inclusions, i.e. it shows a Curie temperatureTC≈ 320 K and metallic-like conductivity. Under high pressure, the low-field room temperature MR undergoes multiple changes in the pressure range up to 7.2 GPa. The structural transition in the ZnGeAs2matrix has been found at ∼6 GPa, slightly lower than in the pure ZnGeAs2(6.2 GPa). The huge SDMR as high as 85% at 6.8 GPa and 2.5 kOe, which contains both positive and negative MR components, is accompanied by a pressure-induced metallic-like-to-semiconductor-like transition and the enhanced ferromagnetic order of MnAs inclusions. This observation offers a competing mechanism between the robust extrinsic ferromagnetism and high-pressure electronic properties of ZnGeAs2.
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Affiliation(s)
- T R Arslanov
- Amirkhanov Institute of Physics, Daghestan Federal Research Center, Russian Academy of Sciences, 367003 Makhachkala, Russia
| | - U Z Zalibekov
- Amirkhanov Institute of Physics, Daghestan Federal Research Center, Russian Academy of Sciences, 367003 Makhachkala, Russia
| | - G G Ashurov
- Amirkhanov Institute of Physics, Daghestan Federal Research Center, Russian Academy of Sciences, 367003 Makhachkala, Russia
| | - Kh Kh Losanov
- Kabardino-Balkarian State University Named After H.M. Berbekov, 360004 Nalchik, Russia
| | - X Zhao
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China
| | - B Dai
- State Key Laboratory for Environment-Friendly Energy Materials, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China
- School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang 621010, People's Republic of China
| | - A I Ril
- Kurnakov Institute of General and Inorganic Chemistry, RAS, 119991 Moscow, Russia
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2
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Cheng Z, Zhang J, Lin L, Zhan Z, Ma Y, Li J, Yu S, Cui H. Pressure-Induced Modulation of Tin Selenide Properties: A Review. Molecules 2023; 28:7971. [PMID: 38138462 PMCID: PMC10745316 DOI: 10.3390/molecules28247971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 11/22/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023] Open
Abstract
Tin selenide (SnSe) holds great potential for abundant future applications, due to its exceptional properties and distinctive layered structure, which can be modified using a variety of techniques. One of the many tuning techniques is pressure manipulating using the diamond anvil cell (DAC), which is a very efficient in situ and reversible approach for modulating the structure and physical properties of SnSe. We briefly summarize the advantages and challenges of experimental study using DAC in this review, then introduce the recent progress and achievements of the pressure-induced structure and performance of SnSe, especially including the influence of pressure on its crystal structure and optical, electronic, and thermoelectric properties. The overall goal of the review is to better understand the mechanics underlying pressure-induced phase transitions and to offer suggestions for properly designing a structural pattern to achieve or enhanced novel properties.
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Affiliation(s)
- Ziwei Cheng
- College of Sciences, Beihua University, Jilin 132013, China; (Z.C.); (Z.Z.); (Y.M.); (J.L.); (S.Y.)
| | - Jian Zhang
- College of Sciences, Beihua University, Jilin 132013, China; (Z.C.); (Z.Z.); (Y.M.); (J.L.); (S.Y.)
| | - Lin Lin
- School of Agricultural Engineering and Food Science, Shandong University of Technology, Zibo 255000, China;
- Key Laboratory of Wooden Materials Science and Engineering of Jilin Province, Beihua University, Jilin 132013, China
| | - Zhiwen Zhan
- College of Sciences, Beihua University, Jilin 132013, China; (Z.C.); (Z.Z.); (Y.M.); (J.L.); (S.Y.)
| | - Yibo Ma
- College of Sciences, Beihua University, Jilin 132013, China; (Z.C.); (Z.Z.); (Y.M.); (J.L.); (S.Y.)
| | - Jia Li
- College of Sciences, Beihua University, Jilin 132013, China; (Z.C.); (Z.Z.); (Y.M.); (J.L.); (S.Y.)
| | - Shenglong Yu
- College of Sciences, Beihua University, Jilin 132013, China; (Z.C.); (Z.Z.); (Y.M.); (J.L.); (S.Y.)
| | - Hang Cui
- State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012, China;
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3
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Zhu S, Wu J, Zhu P, Pei C, Wang Q, Jia D, Wang X, Zhao Y, Gao L, Li C, Cao W, Zhang M, Zhang L, Li M, Gou H, Yang W, Sun J, Chen Y, Wang Z, Yao Y, Qi Y. Pressure-Induced Superconductivity and Topological Quantum Phase Transitions in the Topological Semimetal ZrTe 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2301332. [PMID: 37944509 PMCID: PMC10724415 DOI: 10.1002/advs.202301332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 09/04/2023] [Indexed: 11/12/2023]
Abstract
Topological transition metal dichalcogenides (TMDCs) have attracted much attention due to their potential applications in spintronics and quantum computations. In this work, the structural and electronic properties of topological TMDCs candidate ZrTe2 are systematically investigated under high pressure. A pressure-induced Lifshitz transition is evidenced by the change of charge carrier type as well as the Fermi surface. Superconductivity is observed at around 8.3 GPa without structural phase transition. A typical dome-shape phase diagram is obtained with the maximum Tc of 5.6 K for ZrTe2 . Furthermore, the theoretical calculations suggest the presence of multiple pressure-induced topological quantum phase transitions, which coexists with emergence of superconductivity. The results demonstrate that ZrTe2 with nontrivial topology of electronic states displays new ground states upon compression.
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Affiliation(s)
- Shihao Zhu
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Juefei Wu
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Peng Zhu
- Centre for Quantum PhysicsKey Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE)School of PhysicsBeijing Institute of TechnologyBeijing100081China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic SystemsBeijing Institute of TechnologyBeijing100081China
- Material Science CenterYangtze Delta Region Academy of Beijing Institute of TechnologyJiaxing314011China
| | - Cuiying Pei
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Qi Wang
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
- ShanghaiTech Laboratory for Topological PhysicsShanghaiTech UniversityShanghai201210China
| | - Donghan Jia
- Center for High Pressure Science and Technology Advanced ResearchShanghai201203China
| | - Xinyu Wang
- Center for High Pressure Science and Technology Advanced ResearchShanghai201203China
| | - Yi Zhao
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Lingling Gao
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Changhua Li
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Weizheng Cao
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Mingxin Zhang
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
| | - Lili Zhang
- Shanghai Synchrotron Radiation FacilityShanghai Advanced Research InstituteChinese Academy of SciencesShanghai201203China
| | - Mingtao Li
- Center for High Pressure Science and Technology Advanced ResearchShanghai201203China
| | - Huiyang Gou
- Center for High Pressure Science and Technology Advanced ResearchShanghai201203China
| | - Wenge Yang
- Center for High Pressure Science and Technology Advanced ResearchShanghai201203China
| | - Jian Sun
- National Laboratory of Solid State MicrostructuresSchool of Physics and Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing210093China
| | - Yulin Chen
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
- ShanghaiTech Laboratory for Topological PhysicsShanghaiTech UniversityShanghai201210China
- Department of PhysicsClarendon LaboratoryUniversity of OxfordParks RoadOxfordOX1 3PUUK
| | - Zhiwei Wang
- Centre for Quantum PhysicsKey Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE)School of PhysicsBeijing Institute of TechnologyBeijing100081China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic SystemsBeijing Institute of TechnologyBeijing100081China
- Material Science CenterYangtze Delta Region Academy of Beijing Institute of TechnologyJiaxing314011China
| | - Yugui Yao
- Centre for Quantum PhysicsKey Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE)School of PhysicsBeijing Institute of TechnologyBeijing100081China
- Beijing Key Lab of Nanophotonics and Ultrafine Optoelectronic SystemsBeijing Institute of TechnologyBeijing100081China
| | - Yanpeng Qi
- School of Physical Science and TechnologyShanghaiTech UniversityShanghai201210China
- ShanghaiTech Laboratory for Topological PhysicsShanghaiTech UniversityShanghai201210China
- Shanghai Key Laboratory of High‐resolution Electron MicroscopyShanghaiTech UniversityShanghai201210China
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4
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Ku CH, Liu X, Xie J, Zhang W, Lam ST, Chen Y, Zhou X, Zhao Y, Wang S, Yang S, Lai KT, Goh SK. Patterned diamond anvils prepared via laser writing for electrical transport measurements of thin quantum materials under pressure. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:083912. [PMID: 36050123 DOI: 10.1063/5.0098226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
Quantum materials exhibit intriguing properties with important scientific values and huge technological potential. Electrical transport measurements under hydrostatic pressure have been influential in unraveling the underlying physics of many quantum materials in bulk form. However, such measurements have not been applied widely to samples in the form of thin flakes, in which new phenomena can emerge, due to the difficulty in attaching fine wires to a thin sample suitable for high-pressure devices. Here, we utilize a home-built direct laser writing system to functionalize a diamond anvil to directly integrate the capability of conducting electrical transport measurements of thin flakes with a pressure cell. With our methodology, the culet of a diamond anvil is equipped with a set of custom-designed conducting tracks. We demonstrate the superiority of these tracks as electrodes for the studies of thin flakes by presenting the measurement of pressure-enhanced superconductivity and quantum oscillations in a flake of MoTe2.
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Affiliation(s)
- Che-Hsuan Ku
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Xinyou Liu
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Jianyu Xie
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - W Zhang
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Siu Tung Lam
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Y Chen
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Xuefeng Zhou
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Yusheng Zhao
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Shanmin Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Sen Yang
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Kwing To Lai
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
| | - Swee K Goh
- Department of Physics, The Chinese University of Hong Kong, Shatin N.T., Hong Kong, China
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5
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Niu K, Weng M, Li S, Guo Z, Wang G, Han M, Pan F, Lin J. Direct Visualization of Large-Scale Intrinsic Atomic Lattice Structure and Its Collective Anisotropy in Air-Sensitive Monolayer 1T'- WTe 2. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2101563. [PMID: 34467674 PMCID: PMC8529427 DOI: 10.1002/advs.202101563] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/22/2021] [Indexed: 06/13/2023]
Abstract
Probing large-scale intrinsic structure of air-sensitive 2D materials with atomic resolution is so far challenging due to their rapid oxidization and contamination. Here, by keeping the whole experiment including growth, transfer, and characterizations in an interconnected atmosphere-control environment, the large-scale intact lattice structure of air-sensitive monolayer 1T'-WTe2 is directly visualized by atom-resolved scanning transmission electron microscopy. Benefit from the large-scale atomic mapping, collective lattice distortions are further unveiled due to the presence of anisotropic rippling, which propagates perpendicular to only one of the preferential lattice planes in the same WTe2 monolayer. Such anisotropic lattice rippling modulates the intrinsic point defect (Te vacancy) distribution, in which they aggregate at the constrictive inner side of the undulating structure, presumably due to the ripple-induced asymmetric strain as elaborated by density functional theory. The results pave the way for atomic characterizations and defect engineering of air-sensitive 2D layered materials.
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Affiliation(s)
- Kangdi Niu
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and TechnologyShenzhen518055China
| | - Mouyi Weng
- School of Advanced MaterialsPeking UniversityShenzhen Graduate SchoolShenzhen518055China
| | - Songge Li
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
| | - Zenglong Guo
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
| | - Gang Wang
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
| | - Mengjiao Han
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and TechnologyShenzhen518055China
| | - Feng Pan
- School of Advanced MaterialsPeking UniversityShenzhen Graduate SchoolShenzhen518055China
| | - Junhao Lin
- Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and DevicesSouthern University of Science and TechnologyShenzhen518055China
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6
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Li S, Lei FC, Peng X, Wang RQ, Xie JF, Wu YP, Li DS. Synthesis of Semiconducting 2H-Phase WTe 2 Nanosheets with Large Positive Magnetoresistance. Inorg Chem 2020; 59:11935-11939. [PMID: 32815362 DOI: 10.1021/acs.inorgchem.0c02049] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Tungsten ditelluride (WTe2) is provoking immense interest because of its unique electronic properties, but studies about its semiconducting hexagonal (2H) phase are quite rare. Herein, we report the synthesis of semiconducting 2H WTe2 nanosheets with large positive magnetoresistance, for the first time, by a simple lithium-intercalation-assisted exfoliation strategy. Systematic characterizations including high-resolution transmission electron microscopy, X-ray diffraction, and Raman and X-ray photoelectron spectroscopies provide clear evidence to distinguish the structure of 2H WTe2 nanosheets from the orthorhombic (Td) phase bulk counterpart. The corresponding electronic phase transition from metal to semiconductor is also confirmed by density of states calculation, optical absorption, and electrical transport property measurements. Besides, the 2H WTe2 nanosheets exhibit large positive magnetoresistance with values of up to 29.5% (10 K) and 16.2% (300 K) at 9 T. Overall, these findings open up a promising avenue into the exploration of WTe2-based materials in the semiconductor field.
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Affiliation(s)
- Shuang Li
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang 443002, P. R. China
| | - Feng-Cai Lei
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Xu Peng
- College of Chemistry and Chemical Engineering, Hubei University, Wuhan 430062, P. R. China
| | - Ruo-Qi Wang
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang 443002, P. R. China
| | - Jun-Feng Xie
- College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, P. R. China
| | - Ya-Pan Wu
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang 443002, P. R. China
| | - Dong-Sheng Li
- Key Laboratory of Inorganic Nonmetallic Crystalline and Energy Conversion Materials, College of Materials and Chemical Engineering, China Three Gorges University, Yichang 443002, P. R. China
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7
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Meng J, Chen X, Liu M, Jiang W, Zhang Z, Ling J, Shao T, Yao C, He L, Dou R, Xiong C, Nie J. Large linear magnetoresistance caused by disorder in WTe 2-δthin film. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:355703. [PMID: 32489186 DOI: 10.1088/1361-648x/ab8d74] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Weyl semimetal WTe2has attracted considerable attention owing to its extremely large, unsaturated and quadratic magnetoresistance. Here, we study the magnetotransport properties of WTe2-δthin film, which shows an unsaturated and linear magnetoresistance of up to ∼1650%. A more complex and accurate method, known as the maximum entropy mobility spectrum, is used to analyze the mobility and density of carriers. The results show that linear magnetoresistance can be explained by the classical disorder model because the slope of linear magnetoresistance and the crossover field are proportional to the mobility and inverse mobility, respectively. Furthermore, the validity of the maximum entropy mobility spectrum is validated by the Shubnikov-de Haas oscillations. Moreover, at low temperature, we determined that the unsaturated and near-quadratic magnetoresistance in the WTe1.93thin film can be explained by charge compensation. Note that the electron-hole compensation is broken in the WTe1.42thin film, which indicates that the carrier scattering induced by the disorder may suppress the charge compensation in the WTe2sample with defects/dopants. To summarize, the discovery of disorder-induced linear magnetoresistance allows us to explain different magnetoresistance behaviors of WTe2.
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Affiliation(s)
- Jianchao Meng
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Xinxiang Chen
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Mingrui Liu
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Weimin Jiang
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Zhe Zhang
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jingzhuo Ling
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Tingna Shao
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Chunli Yao
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Lin He
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Ruifen Dou
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Changmin Xiong
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
| | - Jiacai Nie
- Department of Physics, Beijing Normal University, Beijing 100875, People's Republic of China
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8
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Hu YJ, Yu WC, Lai KT, Sun D, Balakirev FF, Zhang W, Xie JY, Yip KY, Aulestia EIP, Jha R, Higashinaka R, Matsuda TD, Yanase Y, Aoki Y, Goh SK. Detection of Hole Pockets in the Candidate Type-II Weyl Semimetal MoTe_{2} from Shubnikov-de Haas Quantum Oscillations. PHYSICAL REVIEW LETTERS 2020; 124:076402. [PMID: 32142308 DOI: 10.1103/physrevlett.124.076402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 11/08/2019] [Accepted: 01/24/2020] [Indexed: 06/10/2023]
Abstract
The bulk electronic structure of T_{d}-MoTe_{2} features large hole Fermi pockets at the Brillouin zone center (Γ) and two electron Fermi surfaces along the Γ-X direction. However, the large hole pockets, whose existence has important implications for the Weyl physics of T_{d}-MoTe_{2}, has never been conclusively detected in quantum oscillations. This raises doubt about the realizability of Majorana states in T_{d}-MoTe_{2}, because these exotic states rely on the existence of Weyl points, which originated from the same band structure predicted by density functional theory (DFT). Here, we report an unambiguous detection of these elusive hole pockets via Shubnikov-de Haas (SdH) quantum oscillations. At ambient pressure, the quantum oscillation frequencies for these pockets are 988 and 1513 T, when the magnetic field is applied along the c axis. The quasiparticle effective masses m^{*} associated with these frequencies are 1.50 and 2.77 m_{e}, respectively, indicating the importance of Coulomb interactions in this system. We further measure the SdH oscillations under pressure. At 13 kbar, we detected a peak at 1798 T with m^{*}=2.86m_{e}. Relative to the oscillation data at a lower pressure, the amplitude of this peak experienced an enhancement, which can be attributed to the reduced curvature of the hole pockets under pressure. Combining our experimental data with DFT+U calculations, where U is the Hubbard parameter, our results shed light on why these important hole pockets have not been detected until now.
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Affiliation(s)
- Y J Hu
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - W C Yu
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
- Department of Physics, City University of Hong Kong, Kowloon, Hong Kong
| | - Kwing To Lai
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - D Sun
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F F Balakirev
- National High Magnetic Field Laboratory, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Zhang
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - J Y Xie
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - K Y Yip
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
| | | | - Rajveer Jha
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Ryuji Higashinaka
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Tatsuma D Matsuda
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Y Yanase
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Yuji Aoki
- Department of Physics, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Swee K Goh
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong
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9
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Wang Y, Wang L, Liu X, Wu H, Wang P, Yan D, Cheng B, Shi Y, Watanabe K, Taniguchi T, Liang SJ, Miao F. Direct Evidence for Charge Compensation-Induced Large Magnetoresistance in Thin WTe 2. NANO LETTERS 2019; 19:3969-3975. [PMID: 31082263 DOI: 10.1021/acs.nanolett.9b01275] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Since the discovery of extremely large nonsaturating magnetoresistance (MR) in WTe2, much effort has been devoted to understanding the underlying mechanism, which is still under debate. Here, we explicitly identify the dominant physical origin of the large nonsaturating MR through in situ tuning of the magneto-transport properties in thin WTe2 film. With an electrostatic doping approach, we observed a nonmonotonic gate dependence of the MR. The MR reaches a maximum (10600%) in thin WTe2 film at certain gate voltage where electron and hole concentrations are balanced, indicating that the charge compensation is the dominant mechanism of the observed large MR. Besides, we show that the temperature-dependent magnetoresistance exhibits similar tendency with the carrier mobility when the charge compensation is retained, revealing that distinct scattering mechanisms may be at play for the temperature dependence of magneto-transport properties. Our work would be helpful for understanding mechanism of the large MR in other nonmagnetic materials and offers an avenue for achieving large MR in the nonmagnetic materials with electron-hole pockets.
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Affiliation(s)
- Yaojia Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Lizheng Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Xiaowei Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Heng Wu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Pengfei Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Dayu Yan
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Bin Cheng
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Youguo Shi
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Kenji Watanabe
- National Institute for Materials Science , 1-1 Namiki Tsukuba , Ibaraki 305-0044 , Japan
| | - Takashi Taniguchi
- National Institute for Materials Science , 1-1 Namiki Tsukuba , Ibaraki 305-0044 , Japan
| | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Feng Miao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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10
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He P, Hsu CH, Shi S, Cai K, Wang J, Wang Q, Eda G, Lin H, Pereira VM, Yang H. Nonlinear magnetotransport shaped by Fermi surface topology and convexity. Nat Commun 2019; 10:1290. [PMID: 30894524 PMCID: PMC6426858 DOI: 10.1038/s41467-019-09208-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/27/2019] [Indexed: 11/09/2022] Open
Abstract
The nature of Fermi surface defines the physical properties of conductors and many physical phenomena can be traced to its shape. Although the recent discovery of a current-dependent nonlinear magnetoresistance in spin-polarized non-magnetic materials has attracted considerable attention in spintronics, correlations between this phenomenon and the underlying fermiology remain unexplored. Here, we report the observation of nonlinear magnetoresistance at room temperature in a semimetal WTe2, with an interesting temperature-driven inversion. Theoretical calculations reproduce the nonlinear transport measurements and allow us to attribute the inversion to temperature-induced changes in Fermi surface convexity. We also report a large anisotropy of nonlinear magnetoresistance in WTe2, due to its low symmetry of Fermi surfaces. The good agreement between experiments and theoretical modeling reveals the critical role of Fermi surface topology and convexity on the nonlinear magneto-response. These results lay a new path to explore ramifications of distinct fermiology for nonlinear transport in condensed-matter.
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Affiliation(s)
- Pan He
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, Singapore, 117576, Singapore
| | - Chuang-Han Hsu
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - Shuyuan Shi
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, Singapore, 117576, Singapore.,Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore
| | - Kaiming Cai
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, Singapore, 117576, Singapore
| | - Junyong Wang
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - Qisheng Wang
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, Singapore, 117576, Singapore
| | - Goki Eda
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, Singapore, 117542, Singapore.,Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore, 117543, Singapore
| | - Hsin Lin
- Institute of Physics, Academia Sinica, Taipei, 11529, Taiwan
| | - Vitor M Pereira
- Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore.,Department of Physics, National University of Singapore, Singapore, 117542, Singapore
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, and NUSNNI, National University of Singapore, Singapore, 117576, Singapore. .,Centre for Advanced 2D Materials, National University of Singapore, Singapore, 117546, Singapore.
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11
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Zhou W, Chen J, Gao H, Hu T, Ruan S, Stroppa A, Ren W. Anomalous and Polarization-Sensitive Photoresponse of T d -WTe 2 from Visible to Infrared Light. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1804629. [PMID: 30516849 DOI: 10.1002/adma.201804629] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/02/2018] [Indexed: 06/09/2023]
Abstract
Recently, an emergent layered material Td -WTe2 was explored for its novel electron-hole overlapping band structure and anisotropic inplane crystal structure. Here, the photoresponse of mechanically exfoliated WTe2 flakes is investigated. A large anomalous current decrease for visible (514.5 nm), and mid- and far-infrared (3.8 and 10.6 µm) laser irradiation is observed, which can be attributed to light-induced surface bandgap opening from the first-principles calculations. The photocurrent and responsivity can be as large as 40 µA and 250 A W-1 for a 3.8 µm laser at 77 K. Furthermore, the WTe2 anomalous photocurrent matches its in-plane crystal structure and exhibits light polarization dependence, maximal for linear laser polarization along the W atom chain a direction and minimal for the perpendicular b direction, with the anisotropic ratio of 4.9. Consistently, first-principles calculations confirm the angle-dependent bandgap opening of WTe2 under polarized light irradiation. The anomalous and polarization-sensitive photoresponses suggest that linearly polarized light can significantly tune the WTe2 surface electronic structure, providing a potential approach to detect polarized and broadband lights up to far infrared range.
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Affiliation(s)
- Wei Zhou
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China
| | - Jingzhe Chen
- Department of Physics, Materials Genome Institute, International Centre for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai, 200444, China
| | - Heng Gao
- Department of Physics, Materials Genome Institute, International Centre for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai, 200444, China
| | - Tao Hu
- Department of Physics, Materials Genome Institute, International Centre for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai, 200444, China
| | - Shuangchen Ruan
- Shenzhen Key Laboratory of Laser Engineering, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | | | - Wei Ren
- Department of Physics, Materials Genome Institute, International Centre for Quantum and Molecular Structures, and Shanghai Key Laboratory of High Temperature Superconductors, Shanghai University, Shanghai, 200444, China
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12
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Li Q, He C, Wang Y, Liu E, Wang M, Wang Y, Zeng J, Ma Z, Cao T, Yi C, Wang N, Watanabe K, Taniguchi T, Shao L, Shi Y, Chen X, Liang SJ, Wang QH, Miao F. Proximity-Induced Superconductivity with Subgap Anomaly in Type II Weyl Semi-Metal WTe 2. NANO LETTERS 2018; 18:7962-7968. [PMID: 30403355 DOI: 10.1021/acs.nanolett.8b03924] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Due to the nontrivial topological band structure in type II Weyl semi-metal tungsten ditelluride (WTe2), unconventional properties may emerge in its superconducting phase. While realizing intrinsic superconductivity has been challenging in the type II Weyl semi-metal WTe2, the proximity effect may open an avenue for the realization of superconductivity. Here, we report the observation of proximity-induced superconductivity with a long coherence length along the c axis in WTe2 thin flakes based on a WTe2/NbSe2 van der Waals heterostructure. Interestingly, we also observe anomalous oscillations of the differential resistance during the transition from the superconducting to the normal state. Theoretical calculations show excellent agreement with experimental results, revealing that such a subgap anomaly is the intrinsic property of WTe2 in superconducting state induced by the proximity effect. Our findings enrich the understanding of the superconducting phase of type II Weyl semi-metals and pave the way for their future applications in topological quantum computing.
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Affiliation(s)
- Qiao Li
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Chaocheng He
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Yaojia Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Erfu Liu
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Miao Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Yu Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Junwen Zeng
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Zecheng Ma
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Tianjun Cao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Changjiang Yi
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Kenji Watanabe
- National Institute for Materials Science , 1-1 Namiki Tsukuba , Ibaraki 305-0044 , Japan
| | - Takashi Taniguchi
- National Institute for Materials Science , 1-1 Namiki Tsukuba , Ibaraki 305-0044 , Japan
| | - Lubing Shao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Youguo Shi
- Institute of Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | | | - Shi-Jun Liang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Qiang-Hua Wang
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Feng Miao
- National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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13
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Wang H, Liu H, Li Y, Liu Y, Wang J, Liu J, Dai JY, Wang Y, Li L, Yan J, Mandrus D, Xie XC, Wang J. Discovery of log-periodic oscillations in ultraquantum topological materials. SCIENCE ADVANCES 2018; 4:eaau5096. [PMID: 30406205 PMCID: PMC6214643 DOI: 10.1126/sciadv.aau5096] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 09/25/2018] [Indexed: 05/30/2023]
Abstract
Quantum oscillations are usually the manifestation of the underlying physical nature in condensed matter systems. Here, we report a new type of log-periodic quantum oscillations in ultraquantum three-dimensional topological materials. Beyond the quantum limit (QL), we observe the log-periodic oscillations involving up to five oscillating cycles (five peaks and five dips) on the magnetoresistance of high-quality single-crystal ZrTe5, virtually showing the clearest feature of discrete scale invariance (DSI). Further, theoretical analyses show that the two-body quasi-bound states can be responsible for the DSI feature. Our work provides a new perspective on the ground state of topological materials beyond the QL.
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Affiliation(s)
- Huichao Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Haiwen Liu
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China
| | - Yanan Li
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Yongjie Liu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Junfeng Wang
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jun Liu
- Center of Electron Microscopy, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Ji-Yan Dai
- Department of Applied Physics, The Hong Kong Polytechnic University, Kowloon, Hong Kong, China
| | - Yong Wang
- Center of Electron Microscopy, State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China
| | - Liang Li
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Jiaqiang Yan
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - David Mandrus
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - X. C. Xie
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
| | - Jian Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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14
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Nonequilibrium Magnetic Oscillation with Cylindrical Vector Beams. Sci Rep 2018; 8:15738. [PMID: 30356070 PMCID: PMC6200753 DOI: 10.1038/s41598-018-33651-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/26/2018] [Indexed: 11/23/2022] Open
Abstract
Magnetic oscillation is a generic property of electronic conductors under magnetic fields and widely appreciated as a useful probe of their electronic band structure, i.e. the Fermi surface geometry. However, the usage of the strong static magnetic field makes the measurement insensitive to the magnetic order of the target material. That is, the magnetic order is anyhow turned into a forced ferrromagnetic one. Here we theoretically propose an experimental method of measuring the magnetic oscillation in a magnetic-order-resolved way by using the azimuthal cylindrical vector (CV) beam, an example of topological lightwaves. The azimuthal CV beam is unique in that, when focused tightly, it develops a pure longitudinal magnetic field. We argue that this characteristic focusing property and the discrepancy in the relaxation timescale between conduction electrons and localized magnetic moments allow us to develop the nonequilibrium analogue of the magnetic oscillation measurement. Our optical method would be also applicable to metals under the ultra-high pressure of diamond anvil cells.
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15
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Zhu L, Li QY, Lv YY, Li S, Zhu XY, Jia ZY, Chen YB, Wen J, Li SC. Superconductivity in Potassium-Intercalated T d-WTe 2. NANO LETTERS 2018; 18:6585-6590. [PMID: 30226053 DOI: 10.1021/acs.nanolett.8b03180] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
To realize a topological superconductor is one of the most attracting topics because of its great potential in quantum computation. In this study, we successfully intercalate potassium (K) into the van der Waals gap of type II Weyl semimetal WTe2 and discover the superconducting state in K xWTe2 through both electrical transport and scanning tunneling spectroscopy measurements. The superconductivity exhibits an evident anisotropic behavior. Moreover, we also uncover the coexistence of superconductivity and the positive magnetoresistance state. Structural analysis substantiates the negligible lattice expansion induced by the intercalation, therefore suggesting K-intercalated WTe2 still hosts the topological nontrivial state. These results indicate that the K-intercalated WTe2 may be a promising candidate to explore the topological superconductor.
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Affiliation(s)
- Li Zhu
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
| | - Qi-Yuan Li
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
| | - Yang-Yang Lv
- National Laboratory of Solid State Microstructures, Department of Materials Science and Engineering , Nanjing University , Nanjing 210093 , China
| | - Shichao Li
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
| | - Xin-Yang Zhu
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
| | - Zhen-Yu Jia
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
| | - Y B Chen
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
- Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Jinsheng Wen
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
- Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
| | - Shao-Chun Li
- National Laboratory of Solid State Microstructures, School of Physics , Nanjing University , Nanjing 210093 , China
- Collaborative Innovation Center of Advanced Microstructures , Nanjing University , Nanjing 210093 , China
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16
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Huang C, Narayan A, Zhang E, Liu Y, Yan X, Wang J, Zhang C, Wang W, Zhou T, Yi C, Liu S, Ling J, Zhang H, Liu R, Sankar R, Chou F, Wang Y, Shi Y, Law KT, Sanvito S, Zhou P, Han Z, Xiu F. Inducing Strong Superconductivity in WTe 2 by a Proximity Effect. ACS NANO 2018; 12:7185-7196. [PMID: 29901987 DOI: 10.1021/acsnano.8b03102] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The search for proximity-induced superconductivity in topological materials has generated widespread interest in the condensed matter physics community. The superconducting states inheriting nontrivial topology at interfaces are expected to exhibit exotic phenomena such as topological superconductivity and Majorana zero modes, which hold promise for applications in quantum computation. However, a practical realization of such hybrid structures based on topological semimetals and superconductors has hitherto been limited. Here, we report the strong proximity-induced superconductivity in type-II Weyl semimetal WTe2, in a van der Waals hybrid structure obtained by mechanically transferring NbSe2 onto various thicknesses of WTe2. When the WTe2 thickness ( tWTe2) reaches 21 nm, the superconducting transition occurs around the critical temperature ( Tc) of NbSe2 with a gap amplitude (Δp) of 0.38 meV and an unexpected ultralong proximity length ( lp) up to 7 μm. With the thicker 42 nm WTe2 layer, however, the proximity effect yields Tc ≈ 1.2 K, Δp = 0.07 meV, and a short lp of less than 1 μm. Our theoretical calculations, based on the Bogoliubov-de Gennes equations in the clean limit, predict that the induced superconducting gap is a sizable fraction of the NbSe2 superconducting one when tWTe2 is less than 30 nm and then decreases quickly as tWTe2 increases. This agrees qualitatively well with the experiments. Such observations form a basis in the search for superconducting phases in topological semimetals.
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Affiliation(s)
- Ce Huang
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Awadhesh Narayan
- Materials Theory , ETH Zurich , Wolfgang-Pauli-Strasse 27 , CH 8093 Zurich , Switzerland
| | - Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Yanwen Liu
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Xiao Yan
- State Key Laboratory of ASIC and System, Department of Microelectronics , Fudan University , Shanghai 200433 , China
| | - Jiaxiang Wang
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Cheng Zhang
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Weiyi Wang
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Tong Zhou
- Department of Physics , The Hong Kong University of Science and Technology , Clear Water Bay , Hong Kong, China
| | - Changjiang Yi
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics , Chinese Academy of Sciences , Beijing 100190 , China
| | - Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Jiwei Ling
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Huiqin Zhang
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Ran Liu
- State Key Laboratory of Surface Physics and Department of Physics , Fudan University , Shanghai 200433 , China
- Institute for Nanoelectronic Devices and Quantum Computing , Fudan University , Shanghai 200433 , China
| | - Raman Sankar
- Institute of Physics , Academia Sinica , Taipei 11529 , Taiwan, China
- Center for Condensed Matter Sciences , National Taiwan University , Taipei 10617 , Taiwan, China
| | - Fangcheng Chou
- Center for Condensed Matter Sciences , National Taiwan University , Taipei 10617 , Taiwan, China
- National Synchrotron Radiation Research Center , Hsinchu 30076 , Taiwan, China
- Taiwan Consortium of Emergent Crystalline Materials , Ministry of Science and Technology , Taipei 10622 , Taiwan, China
| | - Yihua Wang
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Youguo Shi
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics , Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Kam Tuen Law
- Department of Physics , The Hong Kong University of Science and Technology , Clear Water Bay , Hong Kong, China
| | - Stefano Sanvito
- School of Physics, AMBER and CRANN Institute , Trinity College , Dublin 2 , Ireland
| | - Peng Zhou
- State Key Laboratory of ASIC and System, Department of Microelectronics , Fudan University , Shanghai 200433 , China
| | - Zheng Han
- Shenyang National Laboratory for Materials Science, Institute of Metal Research , Chinese Academy of Sciences , Shenyang 110016 , China
| | - Faxian Xiu
- School of Physical Sciences , University of Chinese Academy of Sciences , Beijing 100190 , China
- Collaborative Innovation Center of Advanced Microstructures , Nanjing 210093 , China
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17
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Wang Q, Li J, Besbas J, Hsu C, Cai K, Yang L, Cheng S, Wu Y, Zhang W, Wang K, Chang T, Lin H, Chang H, Yang H. Room-Temperature Nanoseconds Spin Relaxation in WTe 2 and MoTe 2 Thin Films. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2018; 5:1700912. [PMID: 29938171 PMCID: PMC6010885 DOI: 10.1002/advs.201700912] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 02/28/2018] [Indexed: 06/08/2023]
Abstract
The Weyl semimetal WTe2 and MoTe2 show great potential in generating large spin currents since they possess topologically protected spin-polarized states and can carry a very large current density. In addition, the intrinsic non-centrosymmetry of WTe2 and MoTe2 endows with a unique property of crystal symmetry-controlled spin-orbit torques. An important question to be answered for developing spintronic devices is how spins relax in WTe2 and MoTe2. Here, a room-temperature spin relaxation time of 1.2 ns (0.4 ns) in WTe2 (MoTe2) thin film using the time-resolved Kerr rotation (TRKR) is reported. Based on ab initio calculation, a mechanism of long-lived spin polarization resulting from a large spin splitting around the bottom of the conduction band, low electron-hole recombination rate, and suppression of backscattering required by time-reversal and lattice symmetry operation is identified. In addition, it is found that the spin polarization is firmly pinned along the strong internal out-of-plane magnetic field induced by large spin splitting. This work provides an insight into the physical origin of long-lived spin polarization in Weyl semimetals, which could be useful to manipulate spins for a long time at room temperature.
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Affiliation(s)
- Qisheng Wang
- Department of Electrical and Computer Engineering, and NUSNNINational University of SingaporeSingapore117576Singapore
| | - Jie Li
- Center for Joining and Electronic PackagingState Key Laboratory of Material Processing and Die & Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China
| | - Jean Besbas
- Department of Electrical and Computer Engineering, and NUSNNINational University of SingaporeSingapore117576Singapore
| | - Chuang‐Han Hsu
- Department of PhysicsNational University of Singapore2 Science Drive 3Singapore117542Singapore
- Centre for Advanced 2D Materials and Graphene Research CentreNational University of Singapore6 Science Drive 2Singapore117546Singapore
| | - Kaiming Cai
- SKLSMInstitute of SemiconductorsChinese Academy of SciencesP. O. Box 912Beijing100083China
| | - Li Yang
- Center for Joining and Electronic PackagingState Key Laboratory of Material Processing and Die & Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China
| | - Shuai Cheng
- Center for Joining and Electronic PackagingState Key Laboratory of Material Processing and Die & Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China
| | - Yang Wu
- Department of Electrical and Computer Engineering, and NUSNNINational University of SingaporeSingapore117576Singapore
| | - Wenfeng Zhang
- Center for Joining and Electronic PackagingState Key Laboratory of Material Processing and Die & Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China
| | - Kaiyou Wang
- SKLSMInstitute of SemiconductorsChinese Academy of SciencesP. O. Box 912Beijing100083China
| | - Tay‐Rong Chang
- Department of PhysicsNational Cheng Kung UniversityTainan701Taiwan
| | - Hsin Lin
- Department of PhysicsNational University of Singapore2 Science Drive 3Singapore117542Singapore
- Centre for Advanced 2D Materials and Graphene Research CentreNational University of Singapore6 Science Drive 2Singapore117546Singapore
- Institute of PhysicsAcademia SinicaTaipei11529Taiwan
| | - Haixin Chang
- Center for Joining and Electronic PackagingState Key Laboratory of Material Processing and Die & Mould TechnologySchool of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China
| | - Hyunsoo Yang
- Department of Electrical and Computer Engineering, and NUSNNINational University of SingaporeSingapore117576Singapore
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18
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Pressure induced superconductivity bordering a charge-density-wave state in NbTe 4 with strong spin-orbit coupling. Sci Rep 2018; 8:6298. [PMID: 29674609 PMCID: PMC5908920 DOI: 10.1038/s41598-018-24572-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Accepted: 04/06/2018] [Indexed: 11/12/2022] Open
Abstract
Transition-metal chalcogenides host various phases of matter, such as charge-density wave (CDW), superconductors, and topological insulators or semimetals. Superconductivity and its competition with CDW in low-dimensional compounds have attracted much interest and stimulated considerable research. Here we report pressure induced superconductivity in a strong spin-orbit (SO) coupled quasi-one-dimensional (1D) transition-metal chalcogenide NbTe4, which is a CDW material under ambient pressure. With increasing pressure, the CDW transition temperature is gradually suppressed, and superconducting transition, which is fingerprinted by a steep resistivity drop, emerges at pressures above 12.4 GPa. Under pressure p = 69 GPa, zero resistance is detected with a transition temperature Tc = 2.2 K and an upper critical field μ0Hc2 = 2 T. We also find large magnetoresistance (MR) up to 102% at low temperatures, which is a distinct feature differentiating NbTe4 from other conventional CDW materials.
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19
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Fu D, Pan X, Bai Z, Fei F, Umana-Membreno GA, Song H, Wang X, Wang B, Song F. Tuning the electrical transport of type II Weyl semimetal WTe 2 nanodevices by Mo doping. NANOTECHNOLOGY 2018; 29:135705. [PMID: 29432212 DOI: 10.1088/1361-6528/aaa811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We fabricated nanodevices from MoxW1-xTe2 (x = 0, 0.07, 0.35), and conducted a systematic comparative study of their electrical transport. Magnetoresistance measurements show that Mo doping can significantly suppress mobility and magnetoresistance. The results for the analysis of the two band model show that doping with Mo does not break the carrier balance. Through analysis of Shubnikov-de Haas oscillations, we found that Mo doping also has a strong suppressive effect on the quantum oscillation of the sample, and the higher the ratio of Mo, the fewer pockets were observed in our experiments. Furthermore, the effective mass of electron and hole increases gradually with increasing Mo ratio, while the corresponding quantum mobility decreases rapidly.
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Affiliation(s)
- Dongzhi Fu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing, 210093, People's Republic of China
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20
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Li J, Hong M, Sun L, Zhang W, Shu H, Chang H. Enhanced Electrocatalytic Hydrogen Evolution from Large-Scale, Facile-Prepared, Highly Crystalline WTe 2 Nanoribbons with Weyl Semimetallic Phase. ACS APPLIED MATERIALS & INTERFACES 2018; 10:458-467. [PMID: 29235847 DOI: 10.1021/acsami.7b13387] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Tungsten ditellurium (WTe2) is one of most important layered transition metal dichalcogenides (TMDs) and exhibits various prominent physical properties. All the present methods for WTe2 preparation need strict conditions such as high temperature or cannot be applied in large scale, which limits its practical applications. In addition, most studies on WTe2 focus on its physical properties, whereas its electrochemical properties are still illusive with little investigation. Here, we develop a facile and scalable two-step method to synthesize high-quality WTe2 nanoribbon crystals with 1T' Weyl semimetal phase for the first time. Highly crystalline 1T'-WTe2 nanoribbons can be obtained on a large scale through this two-step method. In addition, the electrochemical tests show that WTe2 nanoribbons exhibit smaller overpotential and much better hydrogen evolution reaction catalytic performance than other tungsten-based sulfide and selenide (WS2, WSe2) nanoribbons of same morphology and under same preparation conditions. WTe2 nanoribbons show a Tafel slope of 57 mV/dec, which is one of best values for TMD catalysts and about 2 and 4 times smaller than that for 2H-WS2 nanoribbons (135 mV/dec) and 2H-WSe2 nanoribbons (213 mV/dec), respectively. 1T'-WTe2 nanoribbons also show ultrahigh stability in 5000 cycles and 20 h at 10 mA/cm2. The better performance is attributed to high conductivity of semimetallic 1T'-phase-stable WTe2 nanoribbons with one or two order higher charge-transfer rate than normally semiconducting 2H-stable WS2 and WSe2 nanoribbons. These results open the door for electrochemical applications of Weyl semimetallic TMDs.
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Affiliation(s)
- Jie Li
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Meiling Hong
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
- College of Chemistry and Environmental Engineering, Wuhan Institute of Technology , Wuhan 430073, China
| | - Leijie Sun
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Wenfeng Zhang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
| | - Haibo Shu
- College of Optical and Electronic Technology, China Jiliang Univeristy , Hangzhou 310018, China
| | - Haixin Chang
- Center for Joining and Electronic Packaging, State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology , Wuhan 430074, China
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21
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Abstract
Recently, a type-II Weyl fermion was theoretically predicted to appear at the contact of electron and hole Fermi surface pockets. A distinguishing feature of the surfaces of type-II Weyl semimetals is the existence of topological surface states, so-called Fermi arcs. Although WTe2 was the first material suggested as a type-II Weyl semimetal, the direct observation of its tilting Weyl cone and Fermi arc has not yet been successful. Here, we show strong evidence that WTe2 is a type-II Weyl semimetal by observing two unique transport properties simultaneously in one WTe2 nanoribbon. The negative magnetoresistance induced by a chiral anomaly is quite anisotropic in WTe2 nanoribbons, which is present in b-axis ribbon, but is absent in a-axis ribbon. An extra-quantum oscillation, arising from a Weyl orbit formed by the Fermi arc and bulk Landau levels, displays a two dimensional feature and decays as the thickness increases in WTe2 nanoribbon. Exotic transport properties of type-II Weyl semimetals have been predicted but are yet to be experimentally evidenced. Here, Li et al. report evidences of an anisotropy of negative magnetoresistance and a quantum oscillation arising from the predicted Weyl orbit in the type-II Weyl semimetal WTe2.
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22
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Zhang JL, Guo CY, Zhu XD, Ma L, Zheng GL, Wang YQ, Pi L, Chen Y, Yuan HQ, Tian ML. Disruption of the Accidental Dirac Semimetal State in ZrTe_{5} under Hydrostatic Pressure. PHYSICAL REVIEW LETTERS 2017; 118:206601. [PMID: 28581794 DOI: 10.1103/physrevlett.118.206601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Indexed: 06/07/2023]
Abstract
We study the effect of hydrostatic pressure on the magnetotransport properties of zirconium pentatelluride. The magnitude of resistivity anomaly gets enhanced with increasing pressure, but the transition temperature T^{*} is insensitive to it up to 2.5 GPa. In the case of H∥b, the quasilinear magnetoresistance decreases drastically from 3300% (9 T) at ambient pressure to 230% (9 T) at 2.5 GPa. Besides, the change of the quantum oscillation phase from topological nontrivial to trivial is revealed around 2 GPa. Both demonstrate that the pressure breaks the accidental Dirac node in ZrTe_{5}. For H∥c, in contrast, subtle changes can be seen in the magnetoresistance and quantum oscillations. In the presence of pressure, ZrTe_{5} evolves from a highly anisotropic to a nearly isotropic electronic system, which accompanies the disruption of the accidental Dirac semimetal state. It supports the assumption that ZrTe_{5} is a semi-3D Dirac system with linear dispersion along two directions and a quadratic one along the third.
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Affiliation(s)
- J L Zhang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
| | - C Y Guo
- Department of Physics and Center for Correlated Matter, Zhejiang University, Hangzhou 310027, Zhejiang, People's Republic of China
| | - X D Zhu
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
| | - L Ma
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
| | - G L Zheng
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
| | - Y Q Wang
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
| | - L Pi
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
| | - Y Chen
- Department of Physics and Center for Correlated Matter, Zhejiang University, Hangzhou 310027, Zhejiang, People's Republic of China
| | - H Q Yuan
- Department of Physics and Center for Correlated Matter, Zhejiang University, Hangzhou 310027, Zhejiang, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - M L Tian
- Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory of the Chinese Academy of Sciences, Hefei 230031, Anhui, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
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23
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Anomalous in-plane anisotropic Raman response of monoclinic semimetal 1 T´-MoTe 2. Sci Rep 2017; 7:1758. [PMID: 28496170 PMCID: PMC5431984 DOI: 10.1038/s41598-017-01874-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/13/2017] [Indexed: 11/24/2022] Open
Abstract
The recently discovered two-dimensional (2D) semimetal 1 T´-MoTe2 exhibits colossal magnetoresistance and superconductivity, driving a strong research interest in the material’s quantum phenomena. Unlike the typical hexagonal structure found in many 2D materials, the 1 T´-MoTe2 lattice has strong in-plane anisotropy. A full understanding of the anisotropy is necessary for the fabrication of future devices which may exploit these quantum and topological properties, yet a detailed study of the material’s anisotropy is currently lacking. While angle resolved Raman spectroscopy has been used to study anisotropic 2D materials, such as black phosphorus, there has been no in-depth study of the Raman dependence of 1 T´-MoTe2 on different layer numbers and excitation energies. Here, our angle resolved Raman spectroscopy shows intricate Raman anisotropy dependences of 1 T´-MoTe2 on polarization, flake thickness (from single layer to bulk), photon, and phonon energies. Using a Paczek approximation, the anisotropic Raman response can be captured in a classical framework. Quantum mechanically, first-principle calculations and group theory reveal that the anisotropic electron-photon and electron-phonon interactions are nontrivial in the observed responses. This study is a crucial step to enable potential applications of 1 T´-MoTe2 in novel electronic and optoelectronic devices where the anisotropic properties might be utilized for increased functionality and performance.
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24
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Luo X, Fang C, Wan C, Cai J, Liu Y, Han X, Lu Z, Shi W, Xiong R, Zeng Z. Magnetoresistance and Hall resistivity of semimetal WTe 2 ultrathin flakes. NANOTECHNOLOGY 2017; 28:145704. [PMID: 28103587 DOI: 10.1088/1361-6528/aa5abc] [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
This article reports the characterization of WTe2 thin flake magnetoresistance and Hall resistivity. We found it does not exhibit magnetoresistance saturation when subject to high fields, in a manner similar to their bulk characteristics. The linearity of Hall resistivity in our devices confirms the compensation of electrons and holes. By relating experimental results to a classic two-band model, the lower magnetoresistance values in our samples is demonstrated to be caused by decreased carrier mobility. The dependence of mobility on temperature indicates the main role of optical phonon scattering at high temperatures. Our results provide more detailed information on carrier behavior and scattering mechanisms in WTe2 thin films.
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Affiliation(s)
- Xin Luo
- Key Laboratory of Artificial Micro- and Nano-structures of Ministry of Education, School of Physics and Technology, Wuhan University, Wuhan 430072, People's Republic of China. Key Laboratory of Nanodevices and Applications, Suzhou Institute of Nano-tech and Nano-bionics, Chinese Academy of Sciences, Ruoshui Road 398, Suzhou 215123, People's Republic of China
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25
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Mo SK. Angle-resolved photoemission spectroscopy for the study of two-dimensional materials. NANO CONVERGENCE 2017; 4:6. [PMCID: PMC6141890 DOI: 10.1186/s40580-017-0100-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 03/15/2017] [Indexed: 05/26/2023]
Abstract
Quantum systems in confined geometries allow novel physical properties that cannot easily be attained in their bulk form. These properties are governed by the changes in the band structure and the lattice symmetry, and most pronounced in their single layer limit. Angle-resolved photoemission spectroscopy (ARPES) is a direct tool to investigate the underlying changes of band structure to provide essential information for understanding and controlling such properties. In this review, recent progresses in ARPES as a tool to study two-dimensional atomic crystals have been presented. ARPES results from few-layer and bulk crystals of material class often referred as “beyond graphene” are discussed along with the relevant developments in the instrumentation.
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Affiliation(s)
- Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
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26
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Zhang E, Chen R, Huang C, Yu J, Zhang K, Wang W, Liu S, Ling J, Wan X, Lu HZ, Xiu F. Tunable Positive to Negative Magnetoresistance in Atomically Thin WTe 2. NANO LETTERS 2017; 17:878-885. [PMID: 28033014 DOI: 10.1021/acs.nanolett.6b04194] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Transitional metal ditelluride WTe2 has been extensively studied owing to its intriguing physical properties like nonsaturating positive magnetoresistance and being possibly a type-II Weyl semimetal. While surging research activities were devoted to the understanding of its bulk properties, it remains a substantial challenge to explore the pristine physics in atomically thin WTe2. Here, we report a successful synthesis of mono- to few-layer WTe2 via chemical vapor deposition. Using atomically thin WTe2 nanosheets, we discover a previously inaccessible ambipolar behavior that enables the tunability of magnetoconductance of few-layer WTe2 from weak antilocalization to weak localization, revealing a strong electrical field modulation of the spin-orbit interaction under perpendicular magnetic field. These appealing physical properties unveiled in this study clearly identify WTe2 as a promising platform for exotic electronic and spintronic device applications.
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Affiliation(s)
- Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Rui Chen
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Ce Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Jihai Yu
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Kaitai Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
| | - Weiyi Wang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Jiwei Ling
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
| | - Xiangang Wan
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University , Nanjing 210093, China
| | - Hai-Zhou Lu
- Department of Physics, South University of Science and Technology of China , Shenzhen 518055, China
| | - Faxian Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University , Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University , Nanjing 210093, China
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27
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Song Y, Wang X, Mi W. Spin splitting and reemergence of charge compensation in monolayer WTe2by 3d transition-metal adsorption. Phys Chem Chem Phys 2017; 19:7721-7727. [DOI: 10.1039/c7cp00723j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Transition-metal adsorption effectively modifies the intrinsic properties of monolayer WTe2, where the electron–hole pockets reemerge with Ni adatom.
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Affiliation(s)
- Yan Song
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology
- School of Science
- Tianjin University
- Tianjin 300354
- China
| | - Xiaocha Wang
- School of Electronics Information Engineering
- Tianjin University of Technology
- Tianjin 300384
- China
| | - Wenbo Mi
- Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparation Technology
- School of Science
- Tianjin University
- Tianjin 300354
- China
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28
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Na J, Hoyer A, Schoop L, Weber D, Lotsch BV, Burghard M, Kern K. Tuning the magnetoresistance of ultrathin WTe 2 sheets by electrostatic gating. NANOSCALE 2016; 8:18703-18709. [PMID: 27786318 DOI: 10.1039/c6nr06327f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The semimetallic, two-dimensional layered transition metal dichalcogenide WTe2 has raised considerable interest due to its huge, non-saturating magnetoresistance. While for the origin of this effect, a close-to-ideal balance of electrons and holes has been put forward, the carrier concentration dependence of the magnetoresistance remains to be clarified. Here, we present a detailed study of the magnetotransport behaviour of ultrathin, mechanically exfoliated WTe2 sheets as a function of electrostatic back gating. The carrier concentration and mobility, determined using the two band model and analysis of the Shubnikov-de Haas oscillations, indicate enhanced surface scattering for the thinnest sheets. By the back gate action, the magnetoresistance could be tuned by up to ∼100% for a ∼13 nm-thick WTe2 sheet.
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Affiliation(s)
- Junhong Na
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
| | - Alexander Hoyer
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
| | - Leslie Schoop
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
| | - Daniel Weber
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
| | - Bettina V Lotsch
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
| | - Marko Burghard
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
| | - Klaus Kern
- Max-Planck-Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany. and Institut de Physique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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29
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Wang L, Gutiérrez-Lezama I, Barreteau C, Ki DK, Giannini E, Morpurgo AF. Direct Observation of a Long-Range Field Effect from Gate Tuning of Nonlocal Conductivity. PHYSICAL REVIEW LETTERS 2016; 117:176601. [PMID: 27824454 DOI: 10.1103/physrevlett.117.176601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Indexed: 06/06/2023]
Abstract
We report the direct observation of a long-range field effect in WTe_{2} devices, leading to large gate-induced changes of transport through crystals much thicker than the electrostatic screening length. The phenomenon-which manifests itself very differently from the conventional field effect-originates from the nonlocal nature of transport in the devices that are thinner than the carrier mean free path. We reproduce theoretically the gate dependence of the measured classical and quantum magnetotransport, and show that the phenomenon is caused by the gate tuning of the bulk carrier mobility by changing the scattering at the surface. Our results demonstrate experimentally the possibility to gate tune the electronic properties deep in the interior of conducting materials, avoiding limitations imposed by electrostatic screening.
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Affiliation(s)
- Lin Wang
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Ignacio Gutiérrez-Lezama
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Céline Barreteau
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Dong-Keun Ki
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Enrico Giannini
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
| | - Alberto F Morpurgo
- Department of Quantum Matter Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, University of Geneva, 24 quai Ernest-Ansermet, CH-1211 Geneva, Switzerland
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30
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Zhou Y, Lu P, Du Y, Zhu X, Zhang G, Zhang R, Shao D, Chen X, Wang X, Tian M, Sun J, Wan X, Yang Z, Yang W, Zhang Y, Xing D. Pressure-Induced New Topological Weyl Semimetal Phase in TaAs. PHYSICAL REVIEW LETTERS 2016; 117:146402. [PMID: 27740840 DOI: 10.1103/physrevlett.117.146402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Indexed: 06/06/2023]
Abstract
We report a new pressure-induced phase in TaAs with different Weyl fermions than the ambient structure with the aid of theoretical calculations, experimental transport and synchrotron structure investigations up to 53 GPa. We show that TaAs transforms from an ambient I4_{1}md phase (t-TaAs) to a high-pressure hexagonal P-6m2 (h-TaAs) phase at 14 GPa, along with changes of the electronic state from containing 24 Weyl nodes distributed at two energy levels to possessing 12 Weyl nodes at an isoenergy level, which substantially reduces the interference between the surface and bulk states. The new pressure-induced phase can be reserved upon releasing pressure to ambient condition, which allows one to study the exotic behavior of a single set of Weyl fermions, such as the interplay between surface states and other properties.
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Affiliation(s)
- Yonghui Zhou
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Pengchao Lu
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Yongping Du
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Xiangde Zhu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - Ganghua Zhang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, China
| | - Ranran Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - Dexi Shao
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
| | - Xuliang Chen
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Xuefei Wang
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
| | - Mingliang Tian
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Jian Sun
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiangang Wan
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhaorong Yang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei 230031, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Wenge Yang
- Center for High Pressure Science and Technology Advanced Research (HPSTAR), Shanghai 201203, China
- High Pressure Synergetic Consortium (HPSynC), Geophysical Laboratory, Carnegie Institution of Washington, 9700S Cass Avenue, Argonne, Illinois 60439, USA
| | - Yuheng Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Dingyu Xing
- National Laboratory of Solid State Microstructures, School of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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31
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Coherent optical phonon oscillation and possible electronic softening in WTe2 crystals. Sci Rep 2016; 6:30487. [PMID: 27457385 PMCID: PMC4960623 DOI: 10.1038/srep30487] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/06/2016] [Indexed: 11/09/2022] Open
Abstract
A rapidly-growing interest in WTe2 has been triggered by the giant magnetoresistance effect discovered in this unique system. While many efforts have been made towards uncovering the electron- and spin-relevant mechanisms, the role of lattice vibration remains poorly understood. Here, we study the coherent vibrational dynamics in WTe2 crystals by using ultrafast pump-probe spectroscopy. The oscillation signal in time domain in WTe2 has been ascribed as due to the coherent dynamics of the lowest energy A1 optical phonons with polarization- and wavelength-dependent measurements. With increasing temperature, the phonon energy decreases due to anharmonic decay of the optical phonons into acoustic phonons. Moreover, a significant drop (15%) of the phonon energy with increasing pump power is observed which is possibly caused by the lattice anharmonicity induced by electronic excitation and phonon-phonon interaction.
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32
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Dramatically decreased magnetoresistance in non-stoichiometric WTe2 crystals. Sci Rep 2016; 6:26903. [PMID: 27228908 PMCID: PMC4882502 DOI: 10.1038/srep26903] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 05/10/2016] [Indexed: 12/03/2022] Open
Abstract
Recently, the layered semimetal WTe2 has attracted renewed interest owing to the observation of a non-saturating and giant positive magnetoresistance (~105%), which can be useful for magnetic memory and spintronic devices. However, the underlying mechanisms of the giant magnetoresistance are still under hot debate. Herein, we grew the stoichiometric and non-stoichiometric WTe2 crystals to test the robustness of giant magnetoresistance. The stoichiometric WTe2 crystals have magnetoresistance as large as 3100% at 2 K and 9-Tesla magnetic field. However, only 71% and 13% magnetoresistance in the most non-stoichiometry (WTe1.80) and the highest Mo isovalent substitution samples (W0.7Mo0.3Te2) are observed, respectively. Analysis of the magnetic-field dependent magnetoresistance of non-stoichiometric WTe2 crystals substantiates that both the large electron-hole concentration asymmetry and decreased carrier mobility, induced by non-stoichiometry, synergistically lead to the decreased magnetoresistance. This work sheds more light on the origin of giant magnetoresistance observed in WTe2.
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Lee J, Ye F, Wang Z, Yang R, Hu J, Mao Z, Wei J, Feng PXL. Single- and few-layer WTe2 and their suspended nanostructures: Raman signatures and nanomechanical resonances. NANOSCALE 2016; 8:7854-7860. [PMID: 27030574 DOI: 10.1039/c6nr00492j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Single crystal tungsten ditelluride (WTe2) has recently been discovered to exhibit non-saturating extreme magnetoresistance in bulk; it has also emerged as a new layered material from which atomic layer crystals can be extracted. While atomically thin WTe2 is attractive for its unique properties, little research has been conducted on single- and few-layer WTe2. Here we report the isolation of single- and few-layer WTe2, as well as the fabrication and characterization of the first WTe2 suspended nanostructures. We have observed new Raman signatures of single- and few-layer WTe2 that have been theoretically predicted but have not been reported to date, in both on-substrate and suspended WTe2 flakes. We have further probed the nanomechanical properties of suspended WTe2 structures by measuring their flexural resonances, and obtain a Young's modulus of E(Y) ≈ 80 GPa for the suspended WTe2 flakes. This study paves the way for future investigations and utilizations of the multiple new Raman fingerprints of single- and few-layer WTe2, and for explorations of mechanical control of WTe2 atomic layers.
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Affiliation(s)
- Jaesung Lee
- Department of Electrical Engineering & Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Fan Ye
- Department of Electrical Engineering & Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Zenghui Wang
- Department of Electrical Engineering & Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Rui Yang
- Department of Electrical Engineering & Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Jin Hu
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - Zhiqiang Mao
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - Jiang Wei
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA 70118, USA
| | - Philip X-L Feng
- Department of Electrical Engineering & Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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Song Q, Wang H, Xu X, Pan X, Wang Y, Song F, Wan X, Dai L. The polarization-dependent anisotropic Raman response of few-layer and bulk WTe2under different excitation wavelengths. RSC Adv 2016. [DOI: 10.1039/c6ra23687a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
WTe2, which is an orthorhombic semimetal crystallized in Td phase, exhibts distinct in-plane anisotropy. The Raman modes depict different anisotropic response by rotating the incident polarization under different excitation wavelengths.
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Affiliation(s)
- Qingjun Song
- State Key Lab for Mesoscopic Physics and School of Physics
- Peking University
- Beijing 100871
- China
- Collaborative Innovation Center of Quantum Matter
| | - Haifeng Wang
- National Laboratory of Solid State Microstructures
- College of Physics
- Nanjing University
- Nanjing 210093
- China
| | - Xiaolong Xu
- State Key Lab for Mesoscopic Physics and School of Physics
- Peking University
- Beijing 100871
- China
- Collaborative Innovation Center of Quantum Matter
| | - Xingchen Pan
- National Laboratory of Solid State Microstructures
- College of Physics
- Nanjing University
- Nanjing 210093
- China
| | - Yilun Wang
- State Key Lab for Mesoscopic Physics and School of Physics
- Peking University
- Beijing 100871
- China
- Collaborative Innovation Center of Quantum Matter
| | - Fengqi Song
- National Laboratory of Solid State Microstructures
- College of Physics
- Nanjing University
- Nanjing 210093
- China
| | - Xiangang Wan
- National Laboratory of Solid State Microstructures
- College of Physics
- Nanjing University
- Nanjing 210093
- China
| | - Lun Dai
- State Key Lab for Mesoscopic Physics and School of Physics
- Peking University
- Beijing 100871
- China
- Collaborative Innovation Center of Quantum Matter
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Wang L, Gutiérrez-Lezama I, Barreteau C, Ubrig N, Giannini E, Morpurgo AF. Tuning magnetotransport in a compensated semimetal at the atomic scale. Nat Commun 2015; 6:8892. [PMID: 26600289 PMCID: PMC4673487 DOI: 10.1038/ncomms9892] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/14/2015] [Indexed: 01/21/2023] Open
Abstract
Either in bulk form, or in atomically thin crystals, layered transition metal dichalcogenides continuously reveal new phenomena. The latest example is 1T'-WTe2, a semimetal found to exhibit the largest known magnetoresistance in the bulk, and predicted to become a topological insulator in strained monolayers. Here we show that reducing the thickness through exfoliation enables the electronic properties of WTe2 to be tuned, which allows us to identify the mechanisms responsible for the observed magnetotransport down to the atomic scale. The longitudinal resistance and the unconventional magnetic field dependence of the Hall resistance are reproduced quantitatively by a classical two-band model for crystals as thin as six monolayers, whereas a crossover to an Anderson insulator occurs for thinner crystals. Besides establishing the origin of the magnetoresistance of WTe2, our results represent a complete validation of the classical theory for two-band electron-hole transport, and indicate that atomically thin WTe2 layers remain gapless semimetals.
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Affiliation(s)
- Lin Wang
- Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Ignacio Gutiérrez-Lezama
- Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Céline Barreteau
- Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Nicolas Ubrig
- Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Enrico Giannini
- Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
| | - Alberto F. Morpurgo
- Department of Quantum Matter Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
- Group of Applied Physics, Universite de Geneva, 24 quai Ernest Ansermet, CH-1211 Geneva, Switzerland
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Jiang J, Tang F, Pan XC, Liu HM, Niu XH, Wang YX, Xu DF, Yang HF, Xie BP, Song FQ, Dudin P, Kim TK, Hoesch M, Das PK, Vobornik I, Wan XG, Feng DL. Signature of Strong Spin-Orbital Coupling in the Large Nonsaturating Magnetoresistance Material WTe2. PHYSICAL REVIEW LETTERS 2015; 115:166601. [PMID: 26550888 DOI: 10.1103/physrevlett.115.166601] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Indexed: 06/05/2023]
Abstract
We report the detailed electronic structure of WTe2 by high resolution angle-resolved photoemission spectroscopy. We resolved a rather complicated Fermi surface of WTe2. Specifically, there are in total nine Fermi pockets, including one hole pocket at the Brillouin zone center Γ, and two hole pockets and two electron pockets on each side of Γ along the Γ-X direction. Remarkably, we have observed circular dichroism in our photoemission spectra, which suggests that the orbital angular momentum exhibits a rich texture at various sections of the Fermi surface. This is further confirmed by our density-functional-theory calculations, where the spin texture is qualitatively reproduced as the conjugate consequence of spin-orbital coupling. Since the spin texture would forbid backscatterings that are directly involved in the resistivity, our data suggest that the spin-orbit coupling and the related spin and orbital angular momentum textures may play an important role in the anomalously large magnetoresistance of WTe2. Furthermore, the large differences among spin textures calculated for magnetic fields along the in-plane and out-of-plane directions also provide a natural explanation of the large field-direction dependence on the magnetoresistance.
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Affiliation(s)
- J Jiang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - F Tang
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - X C Pan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - H M Liu
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - X H Niu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - Y X Wang
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - D F Xu
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - H F Yang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology (SIMIT), Chinese Academy of Sciences, Shanghai 200050, China
| | - B P Xie
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
| | - F Q Song
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - P Dudin
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - T K Kim
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - M Hoesch
- Diamond Light Source, Harwell Campus, Didcot OX11 0DE, United Kingdom
| | - P Kumar Das
- CNR-IOM, TASC Laboratory AREA Science Park-Basovizza, 34149 Trieste, Italy
- International Centre for Theoretical Physics, Strada Costiera 11, 34100 Trieste, Italy
| | - I Vobornik
- CNR-IOM, TASC Laboratory AREA Science Park-Basovizza, 34149 Trieste, Italy
| | - X G Wan
- National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, and College of Physics, Nanjing University, Nanjing 210093, People's Republic of China
| | - D L Feng
- State Key Laboratory of Surface Physics, Department of Physics, and Advanced Materials Laboratory, Fudan University, Shanghai 200433, China
- Collaborative Innovation Center of Advanced Microstructures, Fudan University, Shanghai 200433, China
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37
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Wu Y, Jo NH, Ochi M, Huang L, Mou D, Bud'ko SL, Canfield PC, Trivedi N, Arita R, Kaminski A. Temperature-Induced Lifshitz Transition in WTe2. PHYSICAL REVIEW LETTERS 2015; 115:166602. [PMID: 26550889 DOI: 10.1103/physrevlett.115.166602] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Indexed: 06/05/2023]
Abstract
We use ultrahigh resolution, tunable, vacuum ultraviolet laser-based, angle-resolved photoemission spectroscopy (ARPES), temperature- and field-dependent resistivity, and thermoelectric power (TEP) measurements to study the electronic properties of WTe2, a compound that manifests exceptionally large, temperature-dependent magnetoresistance. The Fermi surface consists of two pairs of electron and two pairs of hole pockets along the X-Γ-X direction. Using detailed ARPES temperature scans, we find a rare example of a temperature-induced Lifshitz transition at T≃160 K, associated with the complete disappearance of the hole pockets. Our electronic structure calculations show a clear and substantial shift of the chemical potential μ(T) due to the semimetal nature of this material driven by modest changes in temperature. This change of Fermi surface topology is also corroborated by the temperature dependence of the TEP that shows a change of slope at T≈175 K and a breakdown of Kohler's rule in the 70-140 K range. Our results and the mechanisms driving the Lifshitz transition and transport anomalies are relevant to other systems, such as pnictides, 3D Dirac semimetals, and Weyl semimetals.
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Affiliation(s)
- Yun Wu
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Na Hyun Jo
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Masayuki Ochi
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- JST ERATO Isobe Degenerate π-Integration Project, Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Lunan Huang
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Daixiang Mou
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Sergey L Bud'ko
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - P C Canfield
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
| | - Nandini Trivedi
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ryotaro Arita
- RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan
- JST ERATO Isobe Degenerate π-Integration Project, Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai, Miyagi 980-8577, Japan
| | - Adam Kaminski
- Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA
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Kang D, Zhou Y, Yi W, Yang C, Guo J, Shi Y, Zhang S, Wang Z, Zhang C, Jiang S, Li A, Yang K, Wu Q, Zhang G, Sun L, Zhao Z. Superconductivity emerging from a suppressed large magnetoresistant state in tungsten ditelluride. Nat Commun 2015; 6:7804. [PMID: 26203807 PMCID: PMC4525168 DOI: 10.1038/ncomms8804] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 06/10/2015] [Indexed: 12/24/2022] Open
Abstract
The recent discovery of large magnetoresistance in tungsten ditelluride provides a unique playground to find new phenomena and significant perspective for potential applications. The large magnetoresistance effect originates from a perfect balance of hole and electron carriers, which is sensitive to external pressure. Here we report the suppression of the large magnetoresistance and emergence of superconductivity in pressurized tungsten ditelluride via high-pressure synchrotron X-ray diffraction, electrical resistance, magnetoresistance and alternating current magnetic susceptibility measurements. Upon increasing pressure, the positive large magnetoresistance effect is gradually suppressed and turned off at a critical pressure of 10.5 GPa, where superconductivity accordingly emerges. No structural phase transition is observed under the pressure investigated. In situ high-pressure Hall coefficient measurements at low temperatures demonstrate that elevating pressure decreases the population of hole carriers but increases that of the electron ones. Significantly, at the critical pressure, a sign change of the Hall coefficient is observed.
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Affiliation(s)
- Defen Kang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Yazhou Zhou
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wei Yi
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chongli Yang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Jing Guo
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Youguo Shi
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shan Zhang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhe Wang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Chao Zhang
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Sheng Jiang
- Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China
| | - Aiguo Li
- Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China
| | - Ke Yang
- Shanghai Synchrotron Radiation Facilities, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China
| | - Qi Wu
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Guangming Zhang
- State Key Laboratory for Low dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
| | - Liling Sun
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
| | - Zhongxian Zhao
- Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100190, China
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Pan XC, Chen X, Liu H, Feng Y, Wei Z, Zhou Y, Chi Z, Pi L, Yen F, Song F, Wan X, Yang Z, Wang B, Wang G, Zhang Y. Pressure-driven dome-shaped superconductivity and electronic structural evolution in tungsten ditelluride. Nat Commun 2015; 6:7805. [PMID: 26203922 PMCID: PMC4525151 DOI: 10.1038/ncomms8805] [Citation(s) in RCA: 280] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/10/2015] [Indexed: 12/23/2022] Open
Abstract
Tungsten ditelluride has attracted intense research interest due to the recent discovery of its large unsaturated magnetoresistance up to 60 T. Motivated by the presence of a small, sensitive Fermi surface of 5d electronic orbitals, we boost the electronic properties by applying a high pressure, and introduce superconductivity successfully. Superconductivity sharply appears at a pressure of 2.5 GPa, rapidly reaching a maximum critical temperature (Tc) of 7 K at around 16.8 GPa, followed by a monotonic decrease in Tc with increasing pressure, thereby exhibiting the typical dome-shaped superconducting phase. From theoretical calculations, we interpret the low-pressure region of the superconducting dome to an enrichment of the density of states at the Fermi level and attribute the high-pressure decrease in Tc to possible structural instability. Thus, tungsten ditelluride may provide a new platform for our understanding of superconductivity phenomena in transition metal dichalcogenides.
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Affiliation(s)
- Xing-Chen Pan
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xuliang Chen
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Huimei Liu
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yanqing Feng
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhongxia Wei
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yonghui Zhou
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Zhenhua Chi
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Li Pi
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Fei Yen
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Fengqi Song
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Xiangang Wan
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Zhaorong Yang
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
- Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences, Hefei, Anhui 230031, China
| | - Baigeng Wang
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Guanghou Wang
- National Laboratory of Solid State Microstructures, College of Physics, Nanjing University, Nanjing 210093, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Yuheng Zhang
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui 230031, China
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