Two-Dimensional Arsenene Oxide: A Realistic Large-gap Quantum Spin Hall Insulator

TL;DR

This paper identifies arsenene oxide as a stable 2D material with a large, tunable quantum spin Hall gap suitable for room-temperature topological devices, using ab initio calculations.

Contribution

It introduces arsenene oxide as a new 2D quantum spin Hall insulator with a large, tunable gap, and proposes a quantum well structure for stable topological devices.

Findings

Maximum nontrivial band gap of 89 meV, tunable to 130 meV with strain

Stable against surface oxidation and degradation

Potential for room-temperature quantum spin Hall applications

Abstract

Searching for two-dimensional (2D) realistic materials able to realize room-temperature quantum spin Hall (QSH) effects is currently a growing field. Here, we through ab initio calculations to identify arsenene oxide, AsO, as an excellent candidate, which demonstrates high stability, flexibility, and tunable spin-orbit coupling (SOC) gaps. In contrast to known pristine or functionalized arsenene, the maximum nontrivial band gap of AsO reaches 89 meV, and can be further enhanced to 130 meV under biaxial strain. By sandwiching 2D AsO between BN sheets, we propose a quantum well in which the band topology of AsO is preserved with a sizeable band gap. Considering that AsO having fully oxidized surfaces are naturally stable against surface oxidization and degradation, this functionality provides a viable strategy for designing topological quantum devices operating at room temperature.