Helical edge transport in the presence of a magnetic impurity

TL;DR

This paper investigates how magnetic impurities affect electron transport along the edges of topological insulators, revealing complex voltage-dependent conductance behavior due to scattering effects.

Contribution

It provides a detailed analysis of backscattering caused by magnetic impurities on helical edges, including general exchange interactions and various impurity spins.

Findings

Differential conductance shows non-monotonous voltage dependence.

Multiple extrema appear in the conductance-voltage characteristics.

Backscattering significantly influences edge transport in topological insulators.

Abstract

We consider the effects of electron scattering off a quantum magnetic impurity on the current-voltage characteristics of the helical edge of a two-dimensional topological insulator. We compute the backscattering contribution to the current along the edge for a general form of the exchange interaction matrix and arbitrary value of the magnetic impurity spin. We find that the differential conductance is a non-monotonous function of the voltage with several extrema.