Valence band splitting in bulk dilute bismides

TL;DR

This study uses density functional theory to analyze how bismuth incorporation affects the valence band structure of GaAs, revealing Bi-induced band splitting that varies with atomic configuration and external strain.

Contribution

It provides detailed computational insights into valence band splitting in GaAsBi, highlighting the dependence on local atomic arrangements and external strain effects.

Findings

Bi induces splitting between light-hole and heavy-hole bands

Splitting depends on local Bi atom arrangement

External strain influences band structure

Abstract

The electronic structure of bulk GaAs$_{1-x}$Bi$_x$ systems for different atomic configurations and Bi concentrations is calculated using density functional theory. The results show a Bi-induced splitting between the light-hole and heavy-hole bands at the $\Gamma$-point. We find a good agreement between our calculated splittings and experimental data. The magnitude of the splitting strongly depends on the local arrangement of the Bi atoms but not on the uni-directional lattice constant of the supercell. The additional influence of external strain due to epitaxial growth on GaAs substrates is studied by fixing the in-plane lattice constants.