  We present an investigation of electron-spin dynamics in p-doped bulk GaAs
due to the electron-hole exchange interaction, aka the Bir-Aronov-Pikus
mechanism. We discuss under which conditions a spin relaxation times for this
mechanism is, in principle, accessible to experimental techniques, in
particular to 2-photon photoemission, but also Faraday/Kerr effect
measurements. We give numerical results for the spin relaxation time for a
range of p-doping densities and temperatures. We then go beyond the relaxation
time approximation and calculate numerically the spin-dependent electron
dynamics by including the spin-flip electron-hole exchange scattering and
spin-conserving carrier Coulomb scattering at the level of Boltzmann scattering
integrals. We show that the electronic dynamics deviates from the simple
spin-relaxation dynamics for electrons excited at high energies where the
thermalization does not take place faster than the spin relaxation time. We
also present a derivation of the influence of screening on the electron-hole
exchange scattering and conclude that it can be neglected for the case of GaAs,
but may become important for narrow-gap semiconductors.
