Charge and spin conductivity of a two-dimensional electron gas with random Rashba interaction

TL;DR

This paper investigates how random Rashba spin-orbit interaction affects charge and spin transport in a two-dimensional electron gas, revealing nonmonotonic and decreasing relaxation times that influence conductivity behavior.

Contribution

It provides a theoretical analysis of relaxation times and conductivity in a 2D electron gas with spatially fluctuating Rashba interaction, highlighting their energy dependence.

Findings

Transport relaxation time is nonmonotonic with energy.

Spin relaxation time decreases with increasing energy.

Results imply unusual temperature dependence of conductivities.

Abstract

We calculate the transport relaxation time $\tau _{\rm tr}$ and spin transport relaxation time $\tau _{s,{\rm tr}}$ for a two-dimensional electron gas with spatially fluctuating Rashba spin-orbit interaction. These relaxation times determine the electrical and spin conductivity of the two-dimensional system, respectively. It is shown that the transport relaxation time $\tau _{\rm tr}$ is a nonmonotonic function of electron energy $\varepsilon $, whereas the spin transport relaxation time $\tau _{s,{\rm tr}}$ decreases with increasing $\varepsilon $, similarly to the conventional electron relaxation time $\tau$ that characterizes the decay of an electron state corresponding to certain values of the momentum and spin. Such a behavior of the relaxation times leads to unusual temperature dependence of the electrical and spin conductivity.