Enhanced spin relaxation time due to electron-electron scattering in semiconductors

TL;DR

This paper investigates how electron-electron scattering influences spin relaxation times in 2D electron gases within GaAs/AlGaAs quantum wells, revealing a temperature-dependent enhancement near the Fermi temperature.

Contribution

It provides a combined experimental and theoretical analysis showing electron-electron collisions significantly extend spin relaxation times in 2DEGs, aligning well with the D'yakonov-Perel' mechanism.

Findings

Spin lifetime increases with temperature up to the Fermi temperature.

Experimental results agree with theoretical predictions.

Electron-electron scattering controls spin relaxation dynamics.

Abstract

We present a detailed experimental and theoretical analysis of the spin dynamics of two-dimensional electron gases (2DEGs) in a series of n-doped GaAs/AlGaAs quantum wells. Picosecond-resolution polarized pump-probe reflection techniques were applied in order to study in detail the temperature-, concentration- and quantum-well-width- dependencies of the spin relaxation rate of a small photoexcited electron population. A rapid enhancement of the spin life-time with temperature up to a maximum near the Fermi temperature of the 2DEG was demonstrated experimentally. These observations are consistent with the D'yakonov-Perel' spin relaxation mechanism controlled by electron-electron collisions. The experimental results and theoretical predictions for the spin relaxation times are in good quantitative agreement.