Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)

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 r...

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Autores principales: Chen, P., Pai, Woei Wu, Chan, Y.-H., Sun, W.-L., Xu, C.-Z., Lin, D.-S., Chou, M. Y., Fedorov, A.-V., Chiang, T.-C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2018
Materias:
Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962594/
https://www.ncbi.nlm.nih.gov/pubmed/29784909
http://dx.doi.org/10.1038/s41467-018-04395-2
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author Chen, P.
Pai, Woei Wu
Chan, Y.-H.
Sun, W.-L.
Xu, C.-Z.
Lin, D.-S.
Chou, M. Y.
Fedorov, A.-V.
Chiang, T.-C.
author_facet Chen, P.
Pai, Woei Wu
Chan, Y.-H.
Sun, W.-L.
Xu, C.-Z.
Lin, D.-S.
Chou, M. Y.
Fedorov, A.-V.
Chiang, T.-C.
author_sort Chen, P.
collection PubMed
description 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 WSe(2) single layer with the 1T′ structure that does not exist in the bulk form of WSe(2). 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.
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spelling pubmed-59625942018-05-24 Large quantum-spin-Hall gap in single-layer 1T′ WSe(2) Chen, P. Pai, Woei Wu Chan, Y.-H. Sun, W.-L. Xu, C.-Z. Lin, D.-S. Chou, M. Y. Fedorov, A.-V. Chiang, T.-C. Nat Commun Article 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 WSe(2) single layer with the 1T′ structure that does not exist in the bulk form of WSe(2). 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. Nature Publishing Group UK 2018-05-21 /pmc/articles/PMC5962594/ /pubmed/29784909 http://dx.doi.org/10.1038/s41467-018-04395-2 Text en © The Author(s) 2018 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article′s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article′s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
spellingShingle Article
Chen, P.
Pai, Woei Wu
Chan, Y.-H.
Sun, W.-L.
Xu, C.-Z.
Lin, D.-S.
Chou, M. Y.
Fedorov, A.-V.
Chiang, T.-C.
Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)
title Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)
title_full Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)
title_fullStr Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)
title_full_unstemmed Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)
title_short Large quantum-spin-Hall gap in single-layer 1T′ WSe(2)
title_sort large quantum-spin-hall gap in single-layer 1t′ wse(2)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5962594/
https://www.ncbi.nlm.nih.gov/pubmed/29784909
http://dx.doi.org/10.1038/s41467-018-04395-2
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