‘‘Spin’’-flip scattering of holes in semiconductor quantum wells

We report results of calculations on the ‘‘spin’’-flip relaxation time of holes in semiconductor quantum wells due to hole interaction with static scatterers such as ionized impurities, alloy fluctuations, and s-d exchange (in the case of quantum wells based on diluted magnetic semiconductors). We show that size quantization along the growth axis leads to a drastic quenching of the ‘‘spin’’-flip scattering. This results in hole ‘‘spin’’-flip relaxation times, which can be much longer than the recombination time when the hole in-plane kinetic energy is small compared with the ${\mathrm{HH}}_1$-${\mathrm{LH}}_1$ separation distance.