Temperature dependence of persistent spin currents in a spin-orbit-coupled electron gas: A density-matrix approach

Abstract

We present a simple analytical method, based on the canonical density matrix, for the calculation of the equilibrium spin current as a function of temperature in a two-dimensional electron gas with both Rashba and Dresselhaus spin-orbit coupling terms. We find that the persistent spin current is extremely robust against thermal disorder: its variation with temperature is exponentially small $(\ensuremath{\propto}{e}^{\ensuremath{-}{T}_{F}∕T})$ at temperatures much smaller than the Fermi temperature ${T}_{F}$ and changes to a power law ${T}_{F}∕T$ for $T⪢{T}_{F}$.