Quasi-ballistic-electron transport in random superlattices

© 1994 The American Physical Society. A.S. is thankful to Alan Bishop for warm hospitality at Los Alamos National Laboratory where this paper was written in part. Work at Madrid was supported by UCM through Project No. PR161/93-4811. Work at Leganes was supported by the DGICyT (Spain) through Project No. PB92-0248, and by the European Union Human Capital and Mobility Programrne through Contract No. ERBCHRXCT930413.
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. Interestingly, this phenomenon is also detected in superlattices with random fluctuations of the well thicknesses. Our predictions can be used to demonstrate experimentally that structural correlations inhibit the localization effects of disorder and, most important, that it should be clearly observed even in the presence of imperfections.
UCM
DGICyT (Spain)
European Union
Depto. de Física de Materiales
Fac. de Ciencias Físicas
TRUE
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