Spin relaxation in the presence of electron-electron interactions

TL;DR

This paper investigates how electron-electron interactions affect spin relaxation rates in disordered 2D electron gases, revealing that different measurement techniques yield different rates due to renormalized diffusion constants.

Contribution

It demonstrates that electron-electron interactions cause distinct spin relaxation rates depending on the measurement method, highlighting the importance of renormalized diffusion constants.

Findings

Spin relaxation rate is proportional to the spin-diffusion constant D_s.

Spin-orbit scattering rate is proportional to the conductivity-related diffusion constant D.

Differences in relaxation rates are amplified near magnetic instability or metal-insulator transition.

Abstract

The D'yakonov-Perel' spin relaxation induced by the spin-orbit interaction is examined in disordered two-dimensional electron gas. It is shown that, because of the electron-electron interactions different spin relaxation rates can be obtained depending on the techniques used to extract them. It is demonstrated that the relaxation rate of a spin population is proportional to the spin-diffusion constant D_s, while the spin-orbit scattering rate controlling the weak-localization corrections is proportional to the diffusion constant D, i.e., the conductivity. The two diffusion constants get strongly renormalized by the electron-electron interactions, but in different ways. As a result, the corresponding relaxation rates are different, with the difference between the two being especially strong near a magnetic instability or near the metal-insulator transition.