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Issue 6, 2019
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Topologically nontrivial phase and tunable Rashba effect in half-oxidized bismuthene

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Abstract

Bismuth based (Bi-based) materials exhibit promising potential for the study of two-dimensional (2D) topological insulators or quantum spin Hall (QSH) insulators due to their intrinsic strong spin–orbit coupling (SOC). Herein, we theoretically propose a new inversion-asymmetry topological phase with tunable Rashba effect in a 2D bismuthene monolayer, which is driven by the sublattices half-oxidation (SHO). The nontrivial topology is identified by the SHO induced p–p band inversion at the Γ point, the Z2 topological number, and the metallic edge states. Interestingly, the SOC opens a band gap as large as 0.26 eV at Γ, which is twice as large as that of the freestanding bismuthene monolayer, revealing a predominant contribution of the orbital filtering effect. Inversion-symmetry breaking leads to a substantial Rashba constant of 11.5 eV Å near the valence band top, which is about twice as large as that of the freestanding bismuthene monolayer due to the SHO effect. In particular, the topological insulator-to-topological semimetal phase-transition and the tunable Rashba effect were achieved by exerting a moderate strain. We demonstrate that 3% stretching is the most desirable strain to obtain superior properties. Hexagonal boron nitrogen (h-BN) is proposed to serve as a suitable substrate for SHO-Bi in practical applications. Our findings not only provide a new route to engineering a 2D inversion-asymmetry topological insulator but also represent a significant advance in the exploration of 2D Bi-based topological materials.

Graphical abstract: Topologically nontrivial phase and tunable Rashba effect in half-oxidized bismuthene

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Publication details

The article was received on 14 Oct 2018, accepted on 04 Jan 2019 and first published on 04 Jan 2019


Article type: Paper
DOI: 10.1039/C8CP06391E
Phys. Chem. Chem. Phys., 2019,21, 2899-2909

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    Topologically nontrivial phase and tunable Rashba effect in half-oxidized bismuthene

    M. Liu, Q. Chen, C. Cao and Y. He, Phys. Chem. Chem. Phys., 2019, 21, 2899
    DOI: 10.1039/C8CP06391E

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