Miniband transport and oscillations in semiconductor superlattices

We present and analyse solutions of a recent derivation of a drift-diffusion model of miniband transport in strongly coupled superlattices. The model is obtained from a single-miniband Boltzmann-Poisson transport equation with a BGK (Bhatnagar-Gross-Krook) collision term by means of a consistent Chapman-Enskog expansion. The reduced drift-diffusion equation is solved numerically and travelling field domains and current oscillations are obtained. A broad range of frequencies can be achieved, depending on the model parameters, in good agreement with available experiments on GaAs/AlAs superlattices.