Half-Heusler topological insulators

TL;DR

This paper reviews the potential of half-Heusler compounds as topological insulators, discussing their electronic structures, model Hamiltonians, experimental detection of surface states, and their relevance in topological superconductivity.

Contribution

It introduces the electronic and crystallographic properties of half-Heusler compounds and presents a model Hamiltonian to identify topological states, highlighting their experimental and superconducting aspects.

Findings

Identification of topological surface states in half-Heusler compounds

Effective model Hamiltonian for topological phase prediction

Potential for topological superconductivity in certain materials

Abstract

Ternary semiconducting or metallic half-Heusler compounds with an atomic composition 1:1:1 are widely studied for their flexible electronic properties and functionalities. Recently, a new material property of half-Heusler compounds was predicted based on electronic structure calculations: the topological insulator. In topological insulators, the metallic surface states are protected from impurity backscattering due to spin-momentum locking. This opens up new perspectives in engineering multifunctional materials. In this article, we introduce half Heusler materials from the crystallographic and electronic structure point of view. We present an effective model Hamiltonian from which the topological state can be derived, notably from a non-trivial inverted band structure. We discuss general implications of the inverted band structure with a focus on the detection of the topological surface states in experiments by reviewing several exemplary materials. Special attention is given to superconducting half-Heusler materials, which have attracted ample attention as a platform for non-centrosymmetric and topological superconductivity.