Transport through a quantum spin Hall antidot as a spectroscopic probe of spin textures

TL;DR

This paper explores electron transport through a quantum spin Hall antidot, revealing how current-voltage measurements can probe the spin textures of edge states, especially under broken spin symmetry and Coulomb interactions.

Contribution

It provides an analytical and numerical study of transport in a quantum spin Hall antidot, highlighting how spectroscopic measurements can reveal spin textures.

Findings

Transport properties are profoundly affected by spin-non-conservation.

Current-voltage characteristics enable spectroscopic probing of edge-state spin textures.

The model includes both noninteracting and Coulomb-blockade regimes.

Abstract

We investigate electron transport through an antidot embedded in a narrow strip of two-dimensional topological insulator. We focus on the most generic and experimentally relevant case with broken axial spin symmetry. Spin-non-conservation allows additional scattering processes which change the transport properties profoundly. We start from an analytical model for noninteracting transport, which we also compare with a numerical tight-binding simulation. We then extend this model by including Coulomb repulsion on the antidot, and we study the transport in the Coulomb-blockade limit. We investigate sequential tunneling and cotunneling regimes, and we find that the current-voltage characteristic allows a spectroscopic measurement of the edge-state spin textures.