Electron-electron scattering effect on spin relaxation in multi-valley nanostructures

TL;DR

This paper develops a theory describing how electron-electron collisions influence spin relaxation in multi-valley quantum wells, highlighting differences from single-valley systems and applying it to Si/SiGe structures.

Contribution

It introduces a novel theoretical framework for electron-electron collision effects on spin relaxation in multi-valley quantum wells, specifically applied to Si/SiGe heterostructures.

Findings

Electron-electron scattering rate differs in multi-valley systems from single-valley ones.

Spin relaxation rate depends on temperature, electron concentration, and valley-orbit splitting.

Electron-electron collisions can dominate spin relaxation in high-quality Si/SiGe quantum wells.

Abstract

We develop a theory of effects of electron-electron collisions on the Dyakonov-Perel' spin relaxation in multi-valley quantum wells. It is shown that the electron-electron scattering rate which governs the spin relaxation is different from that in a single-valley system. The theory is applied to Si/SiGe (001)-grown quantum wells where two valleys are simultaneously populated by free carriers. The dependences of the spin relaxation rate on temperature, electron concentration and valley-orbit splitting are calculated and discussed. We demonstrate that in a wide range of temperatures the electron-electron collisions can govern spin relaxation in high-quality Si/SiGe quantum wells.