Evolution of the persistent spin helix in the presence of Hartree-Fock fields

TL;DR

This paper derives a spin diffusion equation for a 2D electron gas with spin-orbit coupling, showing how Hartree-Fock fields from electron interactions can significantly enhance the lifetime of the persistent spin helix and induce polarization rotation.

Contribution

It introduces a new theoretical framework incorporating Hartree-Fock fields into spin diffusion, revealing effects on spin helix stability and polarization dynamics.

Findings

Enhanced persistent spin helix lifetime with large initial spin polarization.

Hartree-Fock field reduces cubic Dresselhaus scattering rate.

Generation of higher harmonics and polarization rotation out of the (Sy,Sz)-plane.

Abstract

We derive a spin diffusion equation for a spin-orbit coupled two-dimensional electron gas including the Hartree-Fock field resulting from 1st order electron-electron interactions. We find that the lifetime of the persistent spin helix, which emerges for equal linear Rashba- and Dresselhaus spin-orbit interactions, can be enhanced considerably for large initial spin polarizations due to the Hartree-Fock field. The reason is a reduction of the symmetry-breaking cubic Dresselhaus scattering rate by the Hartree-Fock field. Also higher harmonics are generated and the polarization of the persistent spin helix rotates out of the (Sy,Sz)-plane acquiring a finite Sx-component. This effect becomes more pronounced, when the cubic Dresselhaus spin-orbit interaction is large.