Adiabatic transformation as a search tool for new topological insulators: distorted ternary Li$_2$AgSb-class semiconductors and related compounds

TL;DR

This paper uses an adiabatic continuation method to predict and classify new topological insulators in ternary Li$_2M'X$ compounds, providing a unified topological phase diagram and demonstrating the method's effectiveness for non-inversion symmetric systems.

Contribution

It introduces a first-principles adiabatic continuation approach to identify and classify topological insulators in complex alloy systems, expanding the toolkit beyond parity analysis.

Findings

Predicted multiple topological insulators in Li$_2M'X$ compounds.

Constructed a comprehensive topological phase diagram.

Identified topologically non-trivial III-V semimetals.

Abstract

We demonstrate that first-principles based adiabatic continuation approach is a very powerful and efficient tool for constructing topological phase diagrams and locating non-trivial topological insulator materials. Using this technique, we predict that the ternary intermetallic series Li$_2M'X$ where $M'$=Cu, Ag, Au, or Cd, and $X$=Sb, Bi, or Sn, hosts a number of topological insulators with remarkable functional variants and tunability. We also predict that several III-V semimetallic compounds are topologically non-trivial. We construct a topological phase diagram in the parameter space of the atomic numbers of atoms in Li$_2M'X$ compounds, which places a large number of topological materials presented in this work as well as in earlier studies within a single unified topological framework. Our results demonstrate the efficacy of adiabatic continuation as a useful tool for exploring topologically nontrivial alloying systems and for identifying new topological insulators even when the underlying lattice does not possess inversion symmetry, and the approaches based on parity analysis are not viable.