Dyakonov-Perel effect on spin dephasing in n-type GaAs

We study the spin dephasing in n-doped bulk GaAs under moderate magnetic fields in Voigt configuration due to the Dyakonov-Perel (DP) effect by constructing and numerically solving the kinetic Bloch equations. Both acoustic (AC) and longitudinal optical (LO) phonon scattering, together with impurity scattering, are included in our theory, and their contributions to the spin dephasing time under the DP effect are examined in detail. The spin dephasing time is obtained from the time evolution of the incoherently summed spin coherence. We investigate how the spin dephasing time is affected by temperature, impurity level, magnetic field, and electron density. In particular, our theory shows that spin dephasing time increases with increasing magnetic field. We find that, contrary to the prediction of previous simplified treatments of the DP effect, the spin dephasing time increases with temperature in the presence of impurity scattering. These results are in qualitative agreement with recent experiments.