Magnetoresistance of vertical transport in InAs/GaSb superlattices

We report a study of the vertical transport of short-period InAs/GaSb superlattices in high parallel magnetic fields. At low magnetic field, the current–voltage characteristic exhibits a double negative differential conductance feature. We attribute the first peak to Esaki–Tsu miniband conduction and the repeat feature to LO-phonon-assisted miniband tunnelling. At high magnetic fields, in the quantum limit we observe a series of conductance peaks that satisfy the Stark-cyclotron-resonance condition. At the magnetophonon condition there is a significant enhancement of these peaks. We explain these observations in terms of the strong k dependence of the miniband width.