Topological phase transitions in bulk

TL;DR

This paper explores the universal features of topological phase transitions in bulk materials, demonstrating that Dirac cones serve as indicators of topological class regardless of disorder or correlations, using ab-initio calculations.

Contribution

It introduces a bulk-based method to determine topological classes through Dirac cones, applicable even in disordered or strongly correlated systems, supported by first-principles calculations.

Findings

Dirac cones are universal markers of topological phase transitions.

Bulk properties can determine topological class despite disorder.

Ab-initio calculations confirm the theoretical predictions.

Abstract

We consider the analogy between the topological phase transition which occurs as a function of spatial coordinate on a surface of a non-trivial insulator, and the one which occurs in the bulk due to the change of internal parameters (such as crystal field and spin-orbit coupling). In both cases the system exhibits a Dirac cone, which is the universal manifestation of topological phase transition, independently on the type of driving parameters. In particular, this leads to a simple way of determining the topological class based solely on the bulk information even for the systems with translational symmetry broken by atomic disorder or by strong electron correlations. Here we demonstrate this on example of the zinc-blende related semiconductors by means of the {\it ab-initio} fully-relativistic band structure calculations involving the coherent potential approximation (CPA) technique.