Reentrant topological phase in half-Heusler compounds

TL;DR

This paper investigates the topological phases of half-Heusler compounds, revealing a reentrant topological phase driven by a three-band mechanism and providing a simple model to interpret these phases.

Contribution

It introduces a new perspective on the topological classification of half-Heusler compounds, emphasizing the role of a previously overlooked $\Gamma_6^*$ state and a three-band mechanism.

Findings

Topological phases are governed by a three-band mechanism.

The $\Gamma_6^*$ state plays a crucial role in topology.

Topological phases are robust under tension.

Abstract

Half-Heusler compounds are known for their various compositions and multifunctional properties including topological phases. In this study, we investigate the topological classification of this class of materials based on the ordering of the $\Gamma_6$, $\Gamma_8$ states, and a previously overlooked $\Gamma_6^*$ state, during an adiabatic expansion process. Using first-principles calculations based on density functional theory, we observed that the non-trivial topology is governed by a three-band mechanism. We provide a simple model derived from $k\cdot p$ Hamiltonian that interprets the topological phase in half-Heusler systems. Additionally, we explore the robustness of the topological phase under tension and a new perspective on the topological nature of half-Heusler compounds.