Effect of electron-electron scattering on spin dephasing in a high-mobility low-density twodimensional electron gas

TL;DR

This study investigates how electron-electron Coulomb scattering influences spin dephasing times in a high-mobility, low-density 2D electron gas, revealing a temperature-dependent maximum in spin relaxation time linked to the crossover from degenerate to nondegenerate regimes.

Contribution

It provides experimental verification of theoretical predictions on the role of electron-electron Coulomb scattering in spin dephasing in 2D electron gases.

Findings

Maximum spin relaxation time of 3.12 ns at 14 K.

Spin relaxation time varies with temperature, peaking at the degenerate-nondegenerate crossover.

Results support the significance of electron-electron Coulomb scattering in spin dynamics.

Abstract

Utilizing time-resolved Kerr rotation techniques, we have investigated the spin dynamics of a high mobility, low density two dimensional electron gas in a GaAs/Al0:35Ga0:65As heterostructure in dependence on temperature from 1.5 K to 30 K. It is found that the spin relaxation/dephasing time under a magnetic field of 0.5 T exhibits a maximum of 3.12 ns around 14 K, superimposed on an increasing background with rising temperature. The appearance of the maximum is ascribed to that at the temperature where the crossover from the degenerate to the nondegenerate regime takes place, electron-electron Coulomb scattering becomes strongest, and thus inhomogeneous precession broadening due to D'yakonov-Perel'(DP) mechanism becomes weakest. These results agree with the recent theoretical predictions [Zhou et al., PRB 75, 045305 (2007)], verifying the importance of electron-electron Coulomb scattering to electron spin relaxation/dephasing.