Nonlinear transport in superlattices under quantizing magnetic fields

The transport in semiconductor superlattices subject to quantizing electric and magnetic fields is studied based on the double-time Green function method. Our rigorous quantum mechanical approach which goes beyond the Kadanoff-Baym ansatz, reveals the hopping nature of the high-field transport in narrow-miniband superlattices. In both the electric- and magnetic-field dependence of the current gaps appear.