Large quantum-spin-Hall gap in single-layer 1T′ WSe2
| Autor: | Alexei V. Fedorov, P. Chen, D. S. Lin, T. C. Chiang, W. W. Pai, Y. H. Chan, W. L. Sun, C. Z. Xu, M. Y. Chou |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Band gap
Photoemission spectroscopy Science General Physics and Astronomy Angle-resolved photoemission spectroscopy 02 engineering and technology 01 natural sciences General Biochemistry Genetics and Molecular Biology law.invention law 0103 physical sciences 010306 general physics lcsh:Science Physics Multidisciplinary Spintronics Condensed matter physics Doping General Chemistry 021001 nanoscience & nanotechnology Topological insulator lcsh:Q Scanning tunneling microscope 0210 nano-technology Bilayer graphene |
| Zdroj: | Nature Communications, Vol 9, Iss 1, Pp 1-7 (2018) Nature communications, vol 9, iss 1 |
| ISSN: | 2041-1723 |
| DOI: | 10.1038/s41467-018-04395-2 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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