Bi alloying is predicted to transform GaAs from a semiconductor to a topological insulator or semi-metal. To date, studies of the GaAs1−xBix alloy band structure have been limited, and the origins of Bi-induced enhancement of the spin-orbit splitting energy, ΔSO, are unresolved. Here, we present high-resolution angle-resolved photoemission spectroscopy (ARPES) of droplet-free epitaxial GaAs1−xBix films with xBi = 0.06. In addition to quantifying the Bi-induced shifts of the light-hole and heavy-hole valence bands, we probe the origins of the Bi-enhanced ΔSO. Using exact-two-component density functional theory calculations, we identify the key role of Bi p-orbitals in the upward shift of the light-hole and heavy-hole bands that results in the Bi-enhanced ΔSO.
@article{arxiv.2511.05335,
title = {Influence of Bi Alloying on GaAs Valence Band Structure},
author = {Joshua J. P. Cooper and Jared W. Mitchell and Shane Smolenski and Ming Wen and Eoghan Downey and Chris Jozwiak and Aaron Bostwick and Eli Rotenberg and Kai Sun and Dominika Zgid and Na Hyun Jo and Rachel S. Goldman},
journal= {arXiv preprint arXiv:2511.05335},
year = {2025}
}