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.