Ultrafast Hole-Spin Dynamics in Optically Excited Bulk GaA

We present experimental and theoretical results on hole-spin dynamics in bulk GaAs after ultrafast optical excitation. The experimental differential transmission are compared with a dynamical calculation of the momentum-resolved hole distributions, which includes the carrier-carrier, carrier-phonon and carrier-impurity interaction at the level of Boltzmann scattering integrals. We obtain good agreement with the experimentally determined hole-spin relaxation times, but point out that depending on how the spin-polarization dynamics is extracted, deviations from an exponential decay at short times occur. We also study theoretically the behavior of the spin-relaxation for heavily p-doped GaAs at low temperatures.