Symmetries and weak (anti)localization of Dirac fermions in HgTe quantum wells

TL;DR

This paper analyzes the symmetries of Dirac fermions in HgTe quantum wells to understand their impact on weak localization and antilocalization phenomena observed in magnetoresistance measurements.

Contribution

It provides a detailed symmetry analysis of the low-energy Hamiltonian and predicts how symmetry-breaking mechanisms influence quantum transport properties.

Findings

Identifies key symmetry-breaking mechanisms affecting localization phenomena.

Predicts patterns of weak localization and antilocalization in HgTe quantum wells.

Connects symmetry properties to observable magnetoresistance effects.

Abstract

We perform a symmetry analysis of a 2D electron system in HgTe/HgCdTe quantum wells in the situation when the chemical potential is outside of the gap, so that the bulk of the quantum well is conducting. In order to investigate quantum transport properties of the system, we explore symmetries of the low-energy Hamiltonian which is expressed in terms of two flavors of Dirac fermions, and physically important symmetry-breaking mechanisms. This allows us to predict emerging patterns of symmetry breaking that control the weak localization and antilocalization showing up in transverse-field magnetoresistance.