Effect of nonequilibrium phonons on hot-electron spin relaxation in n-type GaAs quantum wells

TL;DR

This study investigates how nonequilibrium longitudinal optical phonons affect hot-electron spin relaxation in n-type GaAs quantum wells, revealing their influence on spin relaxation time and precession frequency under various conditions.

Contribution

It is the first to analyze the impact of nonequilibrium phonons on electron spin relaxation in GaAs quantum wells, highlighting their role in modifying electron heating and spin dynamics.

Findings

Spin relaxation time is increased by nonequilibrium phonons.

Spin precession frequency can be increased or decreased depending on conditions.

Nonequilibrium phonon effects are stronger at high electron density and low impurity density.

Abstract

We have studied the effect of nonequilibrium longitudinal optical phonons on hot-electron spin relaxation in $n$-type GaAs quantum wells. The longitudinal optical phonons, due to the finite relaxation rate, are driven to nonequilibrium states by electrons under an in-plane electric field. The nonequilibrium phonons then in turn influence the electron spin relaxation properties via modifying the electron heating and drifting. The spin relaxation time is elongated due to the enhanced electron heating and thus the electron-phonon scattering in the presence of nonequilibrium phonons. The frequency of spin precession, which is roughly proportional to the electron drift velocity, can be either increased (at low electric field and/or high lattice temperature) or decreased (at high electric field and/or low lattice temperature). The nonequilibrium phonon effect is more pronounced when the electron density is high and the impurity density is low.