Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet

Abstract Spin-valley and electronic band topological properties have been extensively explored in quantum material science, yet their coexistence has rarely been realized in stoichiometric two-dimensional (2D) materials. We theoretically predict the quantum spin Hall effect (QSHE) in the hydrofluori...

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Autores principales:	Heng Gao, Wei Wu, Tao Hu, Alessandro Stroppa, Xinran Wang, Baigeng Wang, Feng Miao, Wei Ren
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/944ac5cedd114e18abb42717038cf75f
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spelling	oai:doaj.org-article:944ac5cedd114e18abb42717038cf75f2021-12-02T12:33:00ZSpin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet10.1038/s41598-018-25478-62045-2322https://doaj.org/article/944ac5cedd114e18abb42717038cf75f2018-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-25478-6https://doaj.org/toc/2045-2322Abstract Spin-valley and electronic band topological properties have been extensively explored in quantum material science, yet their coexistence has rarely been realized in stoichiometric two-dimensional (2D) materials. We theoretically predict the quantum spin Hall effect (QSHE) in the hydrofluorinated bismuth (Bi2HF) nanosheet where the hydrogen (H) and fluorine (F) atoms are functionalized on opposite sides of bismuth (Bi) atomic monolayer. Such Bi2HF nanosheet is found to be a 2D topological insulator with a giant band gap of 0.97 eV which might host room temperature QSHE. The atomistic structure of Bi2HF nanosheet is noncentrosymmetric and the spontaneous polarization arises from the hydrofluorinated morphology. The phonon spectrum and ab initio molecular dynamic (AIMD) calculations reveal that the proposed Bi2HF nanosheet is dynamically and thermally stable. The inversion symmetry breaking together with spin-orbit coupling (SOC) leads to the coupling between spin and valley in Bi2HF nanosheet. The emerging valley-dependent properties and the interplay between intrinsic dipole and SOC are investigated using first-principles calculations combined with an effective Hamiltonian model. The topological invariant of the Bi2HF nanosheet is confirmed by using Wilson loop method and the calculated helical metallic edge states are shown to host QSHE. The Bi2HF nanosheet is therefore a promising platform to realize room temperature QSHE and valley spintronics.Heng GaoWei WuTao HuAlessandro StroppaXinran WangBaigeng WangFeng MiaoWei RenNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-8 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Heng Gao Wei Wu Tao Hu Alessandro Stroppa Xinran Wang Baigeng Wang Feng Miao Wei Ren Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet
description	Abstract Spin-valley and electronic band topological properties have been extensively explored in quantum material science, yet their coexistence has rarely been realized in stoichiometric two-dimensional (2D) materials. We theoretically predict the quantum spin Hall effect (QSHE) in the hydrofluorinated bismuth (Bi2HF) nanosheet where the hydrogen (H) and fluorine (F) atoms are functionalized on opposite sides of bismuth (Bi) atomic monolayer. Such Bi2HF nanosheet is found to be a 2D topological insulator with a giant band gap of 0.97 eV which might host room temperature QSHE. The atomistic structure of Bi2HF nanosheet is noncentrosymmetric and the spontaneous polarization arises from the hydrofluorinated morphology. The phonon spectrum and ab initio molecular dynamic (AIMD) calculations reveal that the proposed Bi2HF nanosheet is dynamically and thermally stable. The inversion symmetry breaking together with spin-orbit coupling (SOC) leads to the coupling between spin and valley in Bi2HF nanosheet. The emerging valley-dependent properties and the interplay between intrinsic dipole and SOC are investigated using first-principles calculations combined with an effective Hamiltonian model. The topological invariant of the Bi2HF nanosheet is confirmed by using Wilson loop method and the calculated helical metallic edge states are shown to host QSHE. The Bi2HF nanosheet is therefore a promising platform to realize room temperature QSHE and valley spintronics.
format	article
author	Heng Gao Wei Wu Tao Hu Alessandro Stroppa Xinran Wang Baigeng Wang Feng Miao Wei Ren
author_facet	Heng Gao Wei Wu Tao Hu Alessandro Stroppa Xinran Wang Baigeng Wang Feng Miao Wei Ren
author_sort	Heng Gao
title	Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet
title_short	Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet
title_full	Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet
title_fullStr	Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet
title_full_unstemmed	Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet
title_sort	spin valley and giant quantum spin hall gap of hydrofluorinated bismuth nanosheet
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/944ac5cedd114e18abb42717038cf75f
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Spin valley and giant quantum spin Hall gap of hydrofluorinated bismuth nanosheet

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