  We present a theoretical study of diluted magnetic semiconductors that
includes spin-orbit coupling within a realistic host band structure and treats
explicitly the effects of disorder due to randomly substituted Mn ions. While
spin-orbit coupling reduces the spin polarization by mixing different spin
states in the valence bands, we find that disorder from Mn ions enhances the
spin polarization due to formation of ferromagnetic impurity clusters and
impurity bound states. The disorder leads to large effects on the hole carriers
which form impurity bands as well as hybridizing with the valence band. For Mn
doping 0.01 < x < 0.04, the system is metallic with a large effective mass and
low mobility.
