Theory of Electron Spin Relaxation in n-Doped Quantum Wells

TL;DR

This paper presents a theoretical framework explaining long electron spin lifetimes in n-doped quantum wells by spin exchange mechanisms, accounting for temperature dependence and proposing methods to optimize spin relaxation times.

Contribution

It introduces a comprehensive theory of spin relaxation in quantum wells that incorporates interactions among exciton, localized, and conduction spins, explaining experimental observations.

Findings

Quantitative explanation of temperature-dependent spin relaxation

Identification of spin exchange as key relaxation mechanism

Proposals for optimizing spin lifetimes in quantum wells

Abstract

Recent experiments have demonstrated long spin lifetimes in uniformly n-doped quantum wells. The spin dynamics of exciton, localized, and conduction spins are important for understanding these systems. We explain experimental behavior by invoking spin exchange between all spin species. By doing so we explain quantitatively and qualitatively the striking and unusual temperature dependence in (110)-GaAs quantum wells. We discuss possible future experiments to resolve the pertinent localized spin relaxation mechanisms. In addition, our analysis allows us to propose possible experimental scenarios that will optimize spin relaxation times in GaAs and CdTe quantum wells.