SPIN POLARIZATION OF HOLES ON THE VALENCE-BAND EDGE OF A SEMICONDUCTOR QUANTUM-WELL

The spin relaxation of holes with energies close to the top of the val ence band of an n-type GaAs quantum well is investigated for two spin- flip mechanisms: the electron-hole exchange scattering and the acousti c-phonon-hole scattering. In thicker quantum wells we found the hole-p honon scattering to be the dominant spin-flip mechanism. In narrower w ells the exchange and the hole-phonon spin-flip scatterings have simil ar strengths for holes with energies approaching the valence subband e dge. To provide some elements to contribute to the identification of s uch mechanisms in experimental studies, we have commented on the depen dence of these mechanisms on parameters such as temperature, quantum w ell width and electron density.