Anisotropic conductivity of disordered 2DEGs due to spin-orbit interactions

TL;DR

This paper demonstrates that spin-orbit interactions induce anisotropic conductivity in disordered 2D electron gases, revealing a mesoscopic effect that requires advanced diagrammatic calculations beyond classical approaches.

Contribution

It introduces a detailed diagrammatic analysis showing how Rashba and Dresselhaus SOI cause anisotropic conductivity, highlighting effects overlooked by Boltzmann theory.

Findings

Anisotropic conductivity tensor arises due to SOI.

Anisotropy vanishes with charge dephasing.

Finite anisotropy exists even for infinitesimal SOI at zero frequency.

Abstract

We show that the conductivity tensor of a disordered two-dimensional electron gas becomes anisotropic in the presence of both Rashba and Dresselhaus spin-orbit interactions (SOI). This anisotropy is a mesoscopic effect and vanishes with vanishing charge dephasing time. Using a diagrammatic approach including zero, one, and two-loop diagrams, we show that a consistent calculation needs to go beyond a Boltzmann equation approach. In the absence of charge dephasing and for zero frequency, a finite anisotropy \sigma_{xy} e^2/lhpf arises even for infinitesimal SOI.