Electron spin rephasing in $n$-type (001) GaAs quantum wells

TL;DR

This study explores how electron spin dephasing in GaAs quantum wells can be controlled using pulse sequences, revealing that shorter inter-pulse spacing significantly enhances spin lifetime and that scattering mechanisms play a crucial role.

Contribution

It provides a detailed numerical analysis of spin rephasing effects in GaAs quantum wells, highlighting the importance of pulse timing and scattering processes.

Findings

Shorter inter-pulse spacing increases spin lifetime.

Rephasing pulse sequence has limited effect with long inter-pulse spacing.

Temperature and density effects on spin lifetime relate to scattering times.

Abstract

We investigate the electron spin dephasing in the presence of spin phase recovering by a serried $\pi$-pulse sequence in $n$-type (001) GaAs quantum wells in a wide range of temperature and density regimes. Our numerical calculation is based on the kinetic spin Bloch equation approach with all the relevant scatterings explicitly included. We find that the rephasing pulse sequence with a long inter-pulse spacing only has a marginal influence on the spin lifetime in both the strong and weak scattering limits. We show that the spin lifetime can be significantly increased by reducing the inter-pulse spacing. More interestingly, we show that the temperature and density dependences of the spin lifetime in the case of short inter-pulse spacing coincide with those of the momentum scattering time in the low temperature regime, where nonmonotonic behaviors can appear. The origin of this feature is that the scattering under the quick rephasing manipulation mainly performs as the source of the dephasing channel instead of the key to suppress the inhomogeneous broadening. The contributions of the relevant scattering mechanisms are also discussed.