Unusual Electronic Structure of Few-Layer Grey Arsenic: A Computational Study

TL;DR

This study uses ab initio density functional theory to explore the electronic properties of few-layer grey arsenic, revealing a layer-dependent band gap and a tunable metal-semiconductor transition.

Contribution

It provides new insights into the layer-dependent electronic structure and transition mechanisms of grey arsenic using computational methods.

Findings

Few-layer grey arsenic exhibits a significant, tunable band gap.

A metal-semiconductor transition can be induced by changing layers or strain.

Electronic state distribution changes abruptly at the transition point.

Abstract

We use ab initio density functional theory to study the equilibrium geometry and electronic structure of few-layer grey arsenic. In contrast to the bulk structure that is semimetallic, few-layer grey As displays a significant band gap that depends sensitively on the number of layers, in-layer strain, layer stacking and inter-layer spacing. A metal-semiconductor transition can be introduced by changing the number of layers or the in-layer strain. We interpret this transition by an abrupt change in the spatial distribution of electronic states near the top of the valence band.