Chiral Majorana edge states in HgTe quantum wells

TL;DR

This paper demonstrates how HgTe quantum wells with induced superconductivity and a Zeeman field can host chiral Majorana edge states, advancing the understanding of topological superconductivity in these materials.

Contribution

It provides a theoretical model showing the emergence of chiral Majorana edge states in HgTe quantum wells with proximity-induced superconductivity and magnetic fields.

Findings

Calculation of topological invariants confirming Majorana states

Explicit modeling of edge states in a four-band framework

Inclusion of inversion symmetry breaking effects

Abstract

HgTe-based quantum wells (QWs) recently attracted a lot of attention for the realization of a two-dimensional topological insulator with protected helical edge states. Another class of topological systems are topological superconductors (TSCs) with Majorana edge states. In this paper, we show how proximity induced s-wave superconductivity in the bulk of HgTe-QWs and in the presence of a Zeeman field can exhibit a TSC with chiral Majorana edge states. We calculate the topological invariants and the corresponding Majorana edge states explicitly within a four-band model accounting for inversion symmetry breaking terms due to Rashba spin-orbit coupling and bulk inversion asymmetry present in these QWs.