Magnetic-field-induced charge localization in a high-mobility semiconductor superlattice

The charge distribution of mobile carriers in a high-mobility superlattice is investigated in magnetic fields parallel to the layers. Using a capacitance-voltage profiling technique we are able to directly probe the charge-density distribution as a function of spatial coordinate. With increasing in-plane magnetic field, we observe an increased localization in the potential wells of the superlattice. Using a simple model for the carrier distribution in the superlattice, we are able to calculate the magnetic-field dependence of the miniband structure in the sample. A tight-binding approach results in a quantitative description of the energy level separation as a function of the in-plane magnetic field.