| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Experimental Observations Indicating the Topological Nature of the Edge States on HfTe$_{5}$ |
| Rui-Zhe Liu1,2,3†, Xiong Huang1,3†, Ling-Xiao Zhao1,3†, Li-Min Liu1,3, Jia-Xin Yin4, Rui Wu1,2, Gen-Fu Chen1,3,5, Zi-Qiang Wang6, Shuheng H. Pan1,2,3,5,7** |
1Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190
2Physical Science Laboratory, Huairou National Comprehensive Science Center, Huairou, Beijing 101400
3School of Physics, University of Chinese Academy of Sciences, Beijing 100190
4Laboratory for Topological Quantum Matter and Advanced Spectroscopy (B7), Department of Physics, Princeton University, Princeton, NJ, USA
5Songshan Lake Material Laboratory, Dongguan 523808
6Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA
7CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190
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| Cite this article: |
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Rui-Zhe Liu, Xiong Huang, Ling-Xiao Zhao et al 2019 Chin. Phys. Lett. 36 117301 |
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Abstract The topological edge states of two-dimensional topological insulators with large energy gaps furnish ideal conduction channels for dissipationless current transport. Transition metal tellurides $X$Te$_{5}$ ($X$=Zr, Hf) are theoretically predicted to be large-gap two-dimensional topological insulators, and the experimental observations of their bulk insulating gap and in-gap edge states have been reported, but the topological nature of these edge states still remains to be further elucidated. Here, we report our low-temperature scanning tunneling microscopy/spectroscopy study on single crystals of HfTe$_{5}$. We demonstrate a full energy gap of $\sim$80 meV near the Fermi level on the surface monolayer of HfTe$_{5}$ and that such an insulating energy gap gets filled with finite energy states when measured at the monolayer step edges. Remarkably, such states are absent at the edges of a narrow monolayer strip of one-unit-cell in width but persist at both step edges of a unit-cell wide monolayer groove. These experimental observations strongly indicate that the edge states of HfTe$_{5}$ monolayers are not trivially caused by translational symmetry breaking, instead they are topological in nature protected by the 2D nontrivial bulk properties.
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Received: 03 June 2019
Published: 21 October 2019
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| PACS: |
73.20.-r
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(Electron states at surfaces and interfaces)
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73.22.-f
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(Electronic structure of nanoscale materials and related systems)
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73.43.Jn
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(Tunneling)
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68.37.Ef
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(Scanning tunneling microscopy (including chemistry induced with STM))
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| Fund: Supported by the Chinese Academy of Sciences, the National Natural Science Foundation of China under Grant No 11227903, the BM-STC under Grant No Z181100004218007, the National Basic Research Program of China under Grant Nos 2015CB921300 and 2015CB921304, National Key R&D Program of China under Grant No 2017YFA0302903, the Strategic Priority Research Program B of the Chinese Academy of Sciences under Grant Nos XDB04040300 and XDB07000000, and Beijing Municipal Science & Technology Commission (Z181100004218007). |
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