Phonon assisted momentum relaxation, power dissipation and spin relaxation: Drifted Maxwellian approach

Abstract

Polar optical phonon assisted momentum relaxation, power dissipation and spin relaxation are studied in GaAs. We adopt the drifted Maxwellian approach in the investigation, where the hot phonons are incorporated via the longitudinal polar optical phonon mechanism in the momentum relaxation. Stating from the rate of change of phonon occupancy in a relaxation time approximation, the hot phonon generation and the electronic power dissipation in the drifted Maxwellian are obtained. The results display the runaway effect, where the enhanced scattering rate reduces the drift velocity so that the field at which runaway occurs is increased in order to achieve the necessary power input. Hot phonons thus tend to stabilize the polar interaction and the reduction of drift velocity. The electron temperature and spin relaxation is also found to increase with the electric field. However, at the moderate fields the spins are found to be almost conserved. The spin relaxation is rapid at higher fields and is almost infinite for field higher than 300 mV μm−1, which might be the result of increase of the electron temperature at higher fields and, consequently, the higher Dyakonov-Perel spin relaxation frequency.