Observation of miniband transport in GaAs/Al0.33Ga0.67As superlattices

Abstract

The low temperature current-voltage characteristics of a strongly coupled, short-period GaAs/Al0.33Ga0.67As superlattice structure have been studied with applied magnetic fields both parallel and perpendicular to the current flow. The complex dependence of the current-voltage characteristics on magnetic field perpendicular to the current flow is consistent with a simple model based on Bloch transport via the lowest miniband. From fits to the data the scattering time and mobility have been estimated as 0.15 ps and 4100 cm2/V s, respectively. Further evidence of negative-differential velocity associated with miniband transport comes from the observation of an extended negative-differential resistance region at room temperature in a structure with 50 superlattice repeats.