Experimental observation of conductive edge states in weak topological insulator candidate HfTe5

S. Liu; M. X. Wang; C. Chen; X. Xu; J. Jiang; L. X. Yang; H. F. Yang; Y. Y. Lv; J. Zhou; Y. B. Chen; S. H. Yao; M. H. Lu; Y. F. Chen; C. Felser; B. H. Yan; Z. K. Liu; Y. L. Chen

doi:10.1063/1.5050847

APL Materials (Dec 2018)

Experimental observation of conductive edge states in weak topological insulator candidate HfTe5

S. Liu,
M. X. Wang,
C. Chen,
X. Xu,
J. Jiang,
L. X. Yang,
H. F. Yang,
Y. Y. Lv,
J. Zhou,
Y. B. Chen,
S. H. Yao,
M. H. Lu,
Y. F. Chen,
C. Felser,
B. H. Yan,
Z. K. Liu,
Y. L. Chen

Affiliations

S. Liu: School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, People’s Republic of China
M. X. Wang: School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, People’s Republic of China
C. Chen: Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
X. Xu: State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People’s Republic of China
J. Jiang: School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, People’s Republic of China
L. X. Yang: State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People’s Republic of China
H. F. Yang: School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, People’s Republic of China
Y. Y. Lv: National Laboratory of Solid State Microstructures, School of Physics and Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
J. Zhou: National Laboratory of Solid State Microstructures, School of Physics and Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
Y. B. Chen: National Laboratory of Solid State Microstructures, School of Physics and Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
S. H. Yao: National Laboratory of Solid State Microstructures, School of Physics and Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
M. H. Lu: National Laboratory of Solid State Microstructures, School of Physics and Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
Y. F. Chen: National Laboratory of Solid State Microstructures, School of Physics and Department of Materials Science and Engineering, Nanjing University, Nanjing, Jiangsu 210093, China
C. Felser: Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
B. H. Yan: Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany
Z. K. Liu: School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, People’s Republic of China
Y. L. Chen: School of Physical Science and Technology, ShanghaiTech University and CAS-Shanghai Science Research Center, Shanghai, People’s Republic of China

DOI: https://doi.org/10.1063/1.5050847
Journal volume & issue: Vol. 6, no. 12
pp. 121111 – 121111-8

Abstract

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The quantum spin Hall (QSH) effect is widely studied as a novel quantum state in condensed matter physics over the past decade. Recently, it is predicted that the transition metal pentatelluride XTe5 (X = Zr, Hf) has a large bandgap in its bulk form and a single layer of XTe5 is a QSH insulator candidate. However, the topological nature of the bulk material is still under debate because it is located close to the phase boundary of a strong topological insulator and a weak topological insulator (WTI). Here, using angle-resolved photoemission spectroscopy and scanning tunneling microscopy (STM)/scanning tunneling spectroscopy, we systematically studied the electronic structures of bulk HfTe5. Both the large bulk bandgaps and conductive edge states in the vicinity of the step edges in HfTe5 were observed, strongly suggesting a WTI phase in bulk HfTe5. Moreover, our STM experiment for the first time reveals the bulk band bending due to the broken symmetry near the step edge, making it an ideal platform for studying the development of edge states in the WTI and QSH insulator.

Published in APL Materials

ISSN: 2166-532X (Online)
Publisher: AIP Publishing LLC
Country of publisher: United States
LCC subjects: Technology: Chemical technology: Biotechnology; Science: Physics
Website: http://aplmaterials.aip.org

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