Quasi-Ballistic Electron Transport in Random Superlattices

Abstract

We theoretically study electron transport in disordered, quantum-well based, semiconductor superlattices with structural short-range correlations. Our system consists of equal width square barriers and quantum wells with two different thicknesses. The two kinds of quantum wells are randomly distributed along the growth direction. Structural correlations are introduced by adding the constraint that one of the wells always appears in pairs. We show that such correlated disordered superlattices exhibit a strong enhancement of their dc conductance as compared to usual random ones, giving rise to quasi-ballistic electron transport. Our predictions can be used to demonstrate experimentally that structural correlations inhibit the localization effects of disorder. We specifically describe the way superlattices should be built and experiments should be carried out for that purpose.