Extension of the collision-time tensor to the case of inelastic scatteringmechanisms: Application to GaAs and GaN

In this paper we propose a generalization of the collision time tensor rece ntly introduced for the description of anisotropic but elastic scattering m echanisms to the case of inelastic collision mechanisms (optical phonons). II is shown that this approach brings noticeable corrections to the standar d relaxation time approach as soon as the temperature is lower or of the or der of the Debye temperature associated with the optical phonon energy. Num erical applications are presented in the case of GaAs and GaN. They show th at optical phonon scattering starts to be the preeminent scattering mechani sm well below room temperature for GaAs while acoustical phonon scattering dominates up to 500 K for GaN.