Linear magnetoresistance in HgTe quantum wells

TL;DR

This study investigates magnetotransport in HgTe quantum wells, revealing linear magnetoresistance linked to edge states and disorder effects, with complex resistance behavior at higher magnetic fields.

Contribution

It provides new insights into edge state magnetotransport in topological insulators under magnetic fields, supported by numerical modeling.

Findings

Linear magnetoresistance observed at low fields

Edge state transport suppressed by magnetic field

Resistance behavior at high fields deviates from existing theories

Abstract

We report magnetotransport measurements in a HgTe quantum well with an inverted band structure, which is expected to be a two-dimensional (2D) topological insulator. A small magnetic field perpendicular the 2D layer breaks the time reversal symmetry and thereby, suppresses the edge state transport. A linear magnetoresistance is observed in low magnetic fields, when the chemical potential moves through the the bulk gap. That magnetoresistance is well described by numerical calculations of the edge states magnetotransport in the presence of nonmagnetic disorder. With magnetic field increasing the resistance, measured both in the local and nonlocal configurations first sharply decreases and then increases again in disagreement with the existing theories.