Hole Spin Relaxation in Diluted Magnetic Semiconductors

We used a generalized Pidgeon-Brown model which incorporates the finite $k_{z}$ effects and includes the exchange interaction to calculate the band structure of bulk GaAs and GaMnAs. In Fermi's golden rule approximation, the hole spin relaxation in both bulk GaAs and GaMnAs have been studied. Quantitative calculations show that in intrinsic bulk GaAs, the hole spin life time is around $110$ fs, which is due to phonon scattering. However, in GaMnAs, $p-d$ exchange interaction and high density of impurities provide the other spin flip scattering channels and dominate. The nonequilibrium spin relaxation time is around several fs.