Spin relaxation in multiple (110) quantum wells

TL;DR

This paper theoretically investigates spin relaxation mechanisms in multiple (110) GaAs quantum wells, highlighting how Coulomb screening and electron degeneracy influence relaxation times and dominant processes.

Contribution

It introduces a comprehensive model for spin relaxation in multiple quantum wells, emphasizing the effects of Coulomb screening and electron degeneracy on relaxation mechanisms.

Findings

Screening of Coulomb forces greatly enhances spin relaxation time at low temperatures.

In degenerate gases, Pauli blocking suppresses electron-electron collisions, making donor fields the main relaxation source.

In nondegenerate gases, electron-electron collisions and donor scattering equally contribute to relaxation.

Abstract

We consider theoretically the relaxation of electron spin component parallel to the growth direction in multiple (110) GaAs quantum wells. The sources of spin relaxation are the random Rashba spin-orbit coupling due to the electric field of donors and spin-flip collisions of electrons from different quantum wells. We show that the screening of the Coulomb forces at low temperatures leads to a very strong enhancement of the spin relaxation time. In a degenerate electron gas the Pauli blocking suppresses the electron-electron collisions, and the leading spin relaxation mechanism comes from the field of donors. If the electron gas is nondegenerate the electron-electron collisions and scattering by the ionized donors give similar contributions to the relaxation rate.