| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Evidence of Electron-Hole Imbalance in WTe$_2$ from High-Resolution Angle-Resolved Photoemission Spectroscopy |
| Chen-Lu Wang1,5, Yan Zhang1,5, Jian-Wei Huang1,5, Guo-Dong Liu1,5**, Ai-Ji Liang1, Yu-Xiao Zhang1, Bing Shen1,5, Jing Liu1,5, Cheng Hu1,5, Ying Ding1,5, De-Fa Liu1, Yong Hu1,5, Shao-Long He1, Lin Zhao1, Li Yu1, Jin Hu2, Jiang Wei2, Zhi-Qiang Mao2, You-Guo Shi1, Xiao-Wen Jia3, Feng-Feng Zhang4, Shen-Jin Zhang4, Feng Yang4, Zhi-Min Wang4, Qin-Jun Peng4, Zu-Yan Xu 4, Chuang-Tian Chen4, Xing-Jiang Zhou1,5,6** |
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190
2Department of Physics and Engineering Physics, Tulane University, Louisiana 70118, USA
3General Course Department, Military Transportation University, Tianjin 300161
4Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190
5School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100190
6Collaborative Innovation Center of Quantum Matter, Beijing 100871
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| Cite this article: |
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Chen-Lu Wang, Yan Zhang, Jian-Wei Huang et al 2017 Chin. Phys. Lett. 34 097305 |
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Abstract WTe$_2$ has attracted a great deal of attention because it exhibits extremely large and non-saturating magnetoresistance. The underlying origin of such a giant magnetoresistance is still under debate. Utilizing laser-based angle-resolved photoemission spectroscopy with high energy and momentum resolutions, we reveal the complete electronic structure of WTe$_2$. This makes it possible to determine accurately the electron and hole concentrations and their temperature dependence. We find that, with increasing the temperature, the overall electron concentration increases while the total hole concentration decreases. It indicates that the electron-hole compensation, if it exists, can only occur in a narrow temperature range, and in most of the temperature range there is an electron-hole imbalance. Our results are not consistent with the perfect electron-hole compensation picture that is commonly considered to be the cause of the unusual magnetoresistance in WTe$_2$. We identify a flat band near the Brillouin zone center that is close to the Fermi level and exhibits a pronounced temperature dependence. Such a flat band can play an important role in dictating the transport properties of WTe$_2$. Our results provide new insight on understanding the origin of the unusual magnetoresistance in WTe$_2$.
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Received: 28 May 2017
Published: 15 August 2017
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| PACS: |
73.43.Qt
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(Magnetoresistance)
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74.25.Jb
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(Electronic structure (photoemission, etc.))
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79.60.-i
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(Photoemission and photoelectron spectra)
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71.20.-b
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(Electron density of states and band structure of crystalline solids)
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| Fund: Supported by the National Natural Science Foundation of China under Grant No 11574367, the National Basic Research Program of China under Grant Nos 2013CB921904 and 2015CB921300, the National Key Research and Development Program of China under Grant No 2016YFA0300600, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences under Grant No XDB07020300, and the US Department of Energy under Grant No DE-SC0014208. |
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