Spin Texture and Mirror Chern number in Hg-Based Chalcogenides

TL;DR

This paper investigates the spin textures and topological properties of HgTe and HgS topological insulators, revealing opposite helicities and linking mirror Chern numbers to their topological nature and interface states.

Contribution

It provides a comparative analysis of spin textures and topological invariants in HgTe and HgS, highlighting the role of mirror Chern numbers in their topological classification.

Findings

Opposite spin texture helicities in HgTe and HgS.

Different mirror Chern numbers characterize their topological phases.

Existence of gapless interface states due to topological differences.

Abstract

The unique feature of surface states in topological insulators is the so-called "spin-momentum locking", which means that electron spin is oriented along a fixed direction for a given momentum and forms a texture in the momentum space. In this work, we study spin textures of two typical topological insulators in Hg-Based Chalcogenides, namely HgTe and HgS, based on both the first principles calculation and the eight band Kane model. We find opposite helicities of spin textures between these two materials, originating from the opposite signs of spin-orbit couplings. Furthermore, we reveal that different mirror Chern numbers between HgTe and HgS characterize different topological natures of the systems with opposite spin textures and guarantee the existence of gapless interface states.