Prediction of topological insulating behavior in Hg2CuTi-type Heusler compounds from first principles

TL;DR

This study uses first-principles calculations to predict topological insulating behavior in Hg2CuTi-type Heusler compounds, highlighting their natural band inversion and tunability via strain or alloying for potential material applications.

Contribution

It demonstrates that many Hg2CuTi-type Heusler compounds inherently exhibit topological band inversion, expanding the understanding of topological materials in this family.

Findings

Many compounds show natural band inversion.

Topological properties are tunable by strain or alloying.

Most compounds have negative formation energy.

Abstract

The topological band structures of the X2YZ Heusler compounds with the Hg2CuTi structure are investigated by using first-principles calculations within density functional theory. Our results clearly show that a large number of the Hg2CuTi type Heusler compounds naturally exhibit distinct band-inversion feature, which is mainly controlled by the Y-Z zinc blende sublattice. Similar to the half-Heusler family, the topological band order in Hg2CuTi type Heusler compounds is sensitive to the variation of lattice constant, and most of them possess a negative formation energy, which makes them more suitable in material growth and could easily achieve the topological insulating behavior by alloying or proper strain.