Relaxation mechanisms of the persistent spin helix

TL;DR

This paper investigates the factors affecting the lifetime of the persistent spin helix in semiconductor quantum wells, emphasizing the roles of cubic Dresselhaus interactions and electron-electron interactions, and suggests ways to enhance spin lifetime.

Contribution

It provides a comprehensive semiclassical model that includes impurity scattering, cubic Dresselhaus effects, and electron interactions to explain spin helix lifetime dependence on temperature.

Findings

Cubic Dresselhaus interaction and electron-electron interactions mainly determine spin helix lifetime.

Longer spin lifetimes may be achieved by creating a damped spin profile instead of a persistent helix.

The model aligns with experimental observations of spin relaxation in quantum wells.

Abstract

We study the lifetime of the persistent spin helix in semiconductor quantum wells with equal Rashba- and linear Dresselhaus spin-orbit interactions. In order to address the temperature dependence of the relevant spin relaxation mechanisms we derive and solve semiclassical spin diffusion equations taking into account spin-dependent impurity scattering, cubic Dresselhaus spin-orbit interactions and the effect of electron-electron interactions. For the experimentally relevant regime we find that the lifetime of the persistent spin helix is mainly determined by the interplay of cubic Dresselhaus spin-orbit interaction and electron-electron interactions. We propose that even longer lifetimes can be achieved by generating a spatially damped spin profile instead of the persistent spin helix state.