A mobility calculation for a GaAs/GaAlAs superlattice

We consider a GaAs/GaAIAs superlattice with a small electric field applied perpendicular to the layer planes. The electronic structure is examined in the envelope function approximation and the resulting miniband structure is used in a Boltzmann treatment of the polar optic phonon limited mobility at 300 K. The relaxation time approximation is inadequate due to the inelasticity of the scattering mechanism and the anisotropy of the minibands. We solve the Boltzmann equation exactly using an iterative method and find mobilities which are twice as large as those obtained in the relaxation time approximation.