Structural Transition in Layered As$_{\sf\textbf{1-x}}$P$_{\sf\textbf{x}}$ Compounds: A Computational Study

TL;DR

This computational study investigates how varying arsenic-phosphorus composition in layered 2D heterostructures induces structural transitions and alters electronic properties, including a shift from direct to indirect bandgap.

Contribution

It predicts a composition-dependent structural transition and electronic property change in As$_{1-x}$P$_x$ layered compounds using ab initio density functional theory.

Findings

Structural transition from black phosphorus to grey arsenic allotropes.

Change from direct to indirect bandgap with composition.

Identification of most stable allotropes across compositions.

Abstract

As a way to further improve the electronic properties of group V layered semiconductors, we propose to form in-layer 2D heterostructures of black phosphorus and grey arsenic. We use \textit{ab initio} density functional theory to optimize the geometry, determine the electronic structure, and identify the most stable allotropes as a function of composition. Since pure black phosphorus and pure grey arsenic monolayers differ in their equilibrium structure, we predict a structural transition and a change in frontier states, including a change from a direct-gap to an indirect-gap semiconductor, with changing composition.