# The electronic band structure and optical properties of boron arsenide

## TL;DR

This study uses advanced computational methods to accurately determine the electronic band structure and optical properties of boron arsenide, resolving previous discrepancies and confirming its covalent bonding nature.

## Contribution

The paper applies a relativistic quasiparticle self-consistent GW approach with vertex corrections to improve band structure calculations of boron arsenide, providing more accurate results than previous methods.

## Key findings

- Boron arsenide has an indirect band gap of 1.674 eV.
- The direct band gap is 3.990 eV.
- The material exhibits covalent bonding characteristics.

## Abstract

We compute the electronic band structure and optical properties of boron arsenide using the relativistic quasiparticle self-consistent $GW$ approach, including electron-hole interactions through solution of the Bethe-Salpeter equation. We also calculate its electronic and optical properties using standard and hybrid density functional theory. We demonstrate that the inclusion of self-consistency and vertex corrections provides substantial improvement in the calculated band features, in particular when comparing our results to previous calculations using the single-shot $GW$ approach and various DFT methods, from which a considerable scatter in the calculated indirect and direct band gaps has been observed. We find that BAs has an indirect gap of 1.674 eV and a direct gap of 3.990 eV, consistent with experiment and other comparable computational studies. Hybrid DFT reproduces the indirect gap well, but provides less accurate values for other band features, including spin-orbit splittings. Our computed Born effective charges and dielectric constants confirm the unusually covalent bonding characteristics of this III-V system.