Magnetotransport in disordered two-dimensional topological insulators: signatures of charge puddles

TL;DR

This study numerically examines how disorder, spin-orbit coupling, and magnetic fields affect edge transport in HgTe/CdTe quantum wells, highlighting the role of charge puddles in observed conductance behavior.

Contribution

It demonstrates that charge puddles explain the linear magnetic field dependence of conductance in disordered topological insulators.

Findings

Edge states are robust against moderate disorder and weak magnetic fields.

Charge puddles account for the linear magnetic field dependence of conductance.

Edge transport remains unaffected under realistic conditions.

Abstract

In this numerical study we investigate the influence and interplay of disorder, spin-orbit coupling and magnetic field on the edge-transport in HgTe/CdTe quantum wells in the framework of coherent elastic scattering. We show that the edge states remain unaffected by the combined effect of moderate disorder and a weak magnetic field at realistic spin-orbit coupling strengths. Agreement with the experimentally observed linear magnetic field dependence for the conductance of long samples is obtained when considering the existence of charge puddles.