Combined description for semiclassical and quantum transport in superlattices

The dc current in strongly coupled superlattices can either be described in a semiclassical picture in terms of miniband transport or in a quantum mechanical theory based on hopping transitions between the localized wave functions of the Wannier-Stark ladder. We demonstrate the equivalence of both models in the field regime of Bloch-oscillating electrons. Combining these two pictures we calculate the superlattice drift velocity resulting from microscopic phonon scattering between the Wannier-Stark levels. Our results show that previous discussions of the temperature dependence of the drift velocity have to be revised drastically.