Large quantum-spin-Hall gap in single-layer 1T′ WSe2

被引：132

作者：

Chen, P. ^{[1
,2
,3
]}

Pai, Woei Wu ^{[4
,5
,6
]}

Chan, Y. -H. ^{[7
]}

Sun, W. -L. ^{[8
]}

Xu, C. -Z. ^{[1
,2
]}

Lin, D. -S. ^{[8
]}

Chou, M. Y. ^{[5
,6
,9
]}

Fedorov, A. -V. ^{[3
]}

Chiang, T. -C. ^{[1
,2
,5
]}

机构：

[1] Univ Illinois, Dept Phys, 1110 West Green St, Urbana, IL 61801 USA

[2] Univ Illinois, Frederick Seitz Mat Res Lab, 104 South Goodwin Ave, Urbana, IL 61801 USA

[3] Lawrence Berkeley Natl Lab, Adv Light Source, Berkeley, CA 94720 USA

[4] Natl Taiwan Univ, Ctr Condensed Matter Sci, Taipei 10617, Taiwan

[5] Natl Taiwan Univ, Dept Phys, Taipei 10617, Taiwan

[6] Natl Taiwan Univ, Ctr Atom Initiat New Mat, Taipei 610617, Taiwan

[7] Acad Sinica, Inst Atom & Mol Sci, Taipei 10617, Taiwan

[8] Natl Tsing Hua Univ, Dept Phys, Hsinchu 30013, Taiwan

[9] Georgia Inst Technol, Sch Phys, Atlanta, GA 30332 USA

来源：

NATURE COMMUNICATIONS | 2018年 / 9卷

基金：

美国国家科学基金会;

关键词：

TRANSITION-METAL DICHALCOGENIDES; TOTAL-ENERGY CALCULATIONS; AUGMENTED-WAVE METHOD; EPITAXIAL-GROWTH; BASIS-SET; SEMICONDUCTOR; INSULATORS; SURFACE; STATE; WELLS;

D O I：

10.1038/s41467-018-04395-2

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum-spin-Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for room-temperature applications has proven difficult. Here, we report the successful growth on bilayer graphene of a quasi-freestanding WSe2 single layer with the 1T' structure that does not exist in the bulk form of WSe2. Using angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy/spectroscopy (STM/STS), we observe a gap of 129 meV in the 1T' layer and an in-gap edge state located near the layer boundary. The system's 2D TI characters are confirmed by first-principles calculations. The observed gap diminishes with doping by Rb adsorption, ultimately leading to an insulator-semimetal transition. The discovery of this large-gap 2D TI with a tunable band gap opens up opportunities for developing advanced nanoscale systems and quantum devices.

引用

页数：7

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