Topological phase diagram of Pb1-xSnxSe1-yTey

TL;DR

This paper constructs a detailed topological phase diagram for the quaternary compound Pb1-xSnxSe1-yTey using advanced computational methods, accurately capturing various topological phases including Weyl phases.

Contribution

It combines density functional theory and tight-binding models to reproduce and extend the topological phase diagram of Pb1-xSnxSe1-yTey, including the Weyl phase.

Findings

Calculated the mirror Chern number as a function of x and y.

Identified the transition line between trivial and topological phases.

Predicted the presence of Weyl phases in the phase diagram.

Abstract

We reproduce the mirror Chern number phase diagram for the quaternary compound Pb1-xSnxSe1-yTey combining accurate density functional theory and tight-biding model. The tight binding models are extracted from ab-initio results, adding constraints to reproduce the experimental results. By using the virtual crystalline approximation, we calculated the mirror Chern number as a function of the concentrations x and y. We report different hamiltonians depending on whether we want to focus on the experimental band gap or on the experimental topological transition. We calculate the transition line between the trivial insulating phase and topological insulating phase that results in good agreement with the experimental results. Finally, we add in the phase diagram the Weyl phase predicted in the literature providing a complete topological phase diagram for the Pb1-xSnxSe1-yTey quaternary compound.