On the Quantum Spin Hall Gap of Monolayer 1T'-WTe2

Feipeng Zheng; Chaoyi Cai; Shaofeng Ge; Xuefeng Zhang; Xin Liu; Hong Lu; Yudao Zhang; Jun Qiu; Takashi Taniguchi; Kenji Watanabe; Shuang Jia; Jingshan Qi; Jian-Hao Chen; Dong Sun; Ji Feng

doi:10.1002/adma.201600100

On the Quantum Spin Hall Gap of Monolayer 1T'-WTe2

Adv Mater. 2016 Jun;28(24):4845-51. doi: 10.1002/adma.201600100. Epub 2016 Apr 26.

Authors

Feipeng Zheng^{1

2}, Chaoyi Cai^{1

2}, Shaofeng Ge^{1

2}, Xuefeng Zhang³, Xin Liu^{1

2}, Hong Lu^{1

2}, Yudao Zhang^{1

2}, Jun Qiu^{1

2}, Takashi Taniguchi⁴, Kenji Watanabe⁴, Shuang Jia^{1

2}, Jingshan Qi⁵, Jian-Hao Chen^{1

2}, Dong Sun^{1

2}, Ji Feng^{1

2}

Affiliations

¹ International Center for Quantum Materials, School of Physics, Peking University, Beijing, 100871, P. R. China.
² Collaborative Center for Materials Innovation, Beijing, 100871, P. R. China.
³ School of Physics and Engineering, Zhengzhou University, Zhengzhou, 450001, P. R. China.
⁴ High Pressure Group, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
⁵ School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, 221116, P. R. China.

PMID: 27115098
DOI: 10.1002/adma.201600100

Abstract

Positive quantum spin Hall gap in mono-layer 1T'-WTe2 is consistently supported by density-functional theory calculations, ultrafast pump-probe, and electrical transport measurements. It is argued that monolayer 1T'-WTe2 , which was predicted to be a semimetallic quantum spin Hall material, is likely a truly 2D quantum spin Hall insulator with a positive quantum spin Hall gap.

Keywords: Schottcky junctions; density functional theory; quantum spin Hall effect; ultra-fast spectroscopy.