Article

2020; 20(3): 413-418

Published online January 8, 2020 https://doi.org/10.1016/j.cap.2019.12.009

Copyright © The Korean Physical Society.

Spin-orbit coupling-induced band inversion and spin Chern insulator phase in plumbene and stanene

Lee K.W., Lee C.E.

Department of Physics, Korea University, Seoul, 02841, South Korea

Correspondence to:Lee, Cheol Eui
Department of Physics, Korea University

Received: April 7, 2019; Accepted: December 28, 2019

Abstract

Z2 topology in two-dimensional group IVA materials has been explained by the band orders due to the crystal field splitting at the Γ point in the Brillouin zone, while spin-orbit coupling (SOC) was considered just to open a band gap. By using a multi-orbital tight-binding model, we show that the SOC induces band inversion between the conduction and valence bands at the Γ point in plumbene, which also is the case in stanene when the SOC strength increases. As a result of the band inversion, plumbene becomes a spin Chern insulator with a spin Chern number CS = 2 and, as the SOC strength increases, stanene undergoes a topological phase transition from a Z2 topological insulator to a spin Chern insulator with CS = 2. Under a staggered AB-sublattice potential, plumbene undergoes a phase transition from the spin Chern insulator with CS = 2 to a Z2 topological insulator with CS = 1. © 2020 Korean Physical Society

Keywords: Band inversion, Plumbene, Spin Chern insulator, Stanene, Z2 topology

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