Disorder-induced topological phase transition in HgCdTe crystals

TL;DR

This paper investigates how uncorrelated disorder induces a topological phase transition in bulk HgCdTe crystals, revealing the role of disorder in altering topological properties and identifying conditions for phase change.

Contribution

The study introduces a theoretical framework using the self-consistent Born approximation to analyze disorder effects on topological phases in HgCdTe, highlighting the influence of heavy-hole bands.

Findings

Disorder induces a topological phase transition in HgCdTe.

Heavy-hole bands lower the disorder threshold for phase transition.

Results applicable to other narrow-gap zinc-blende semiconductors.

Abstract

Using the self-consistent Born approximation, we study a topological phase transition appearing in bulk HgCdTe crystals induced \emph{uncorrelated} disorder due to both randomly distributed impurities and fluctuations in Cd composition. By following the density-of-states evolution, we clearly demonstrate the topological phase transition, which can be understood in terms of the disorder-renormalized mass of Kane fermions. We find that the presence of heavy-hole band in HgCdTe crystals leads to the topological phase transition at much lower disorder strength than it is expected for conventional 3D topological insulators. Our theoretical results can be also applied to other narrow-gap zinc-blende semiconductors such as InAs, InSb and their ternary alloys InAsSb.