Unfolding the band structure of disordered solids: from bound states to high-mobility Kane fermions

TL;DR

This paper introduces a spectral weight approach to unfold the electronic structure of disordered solids, revealing phenomena like band anticrossing and high-mobility Kane fermions, aiding interpretation of optical and transport properties.

Contribution

The study presents a novel spectral weight method for unfolding supercell electronic structures, enabling clearer analysis of disorder effects in semiconductor alloys.

Findings

Observation of donor-like states in Ga(PN)

Detection of valence band anticrossing in GaAs:Bi

Identification of high-mobility Kane fermions in HgCdTe

Abstract

Supercells are often used in ab initio calculations to model compound alloys, surfaces and defects. One of the main challenges of supercell electronic structure calculations is to recover the Bloch character of electronic eigenstates perturbed by disorder. Here we apply the spectral weight approach to unfolding the electronic structure of group III-V and II-VI semiconductor solid solutions. The illustrative examples include: formation of donor-like states in dilute Ga(PN) and associated enhancement of its optical activity, direct observation of the valence band anticrossing in dilute GaAs:Bi, and a topological band crossover in ternary (HgCd)Te alloy accompanied by emergence of high-mobility Kane fermions. The analysis facilitates interpretation of optical and transport characteristics of alloys that are otherwise ambiguous in traditional first-principles supercell calculations.