Nonlinear and oscillatory electronic transport in superlattices as a probe of structural imperfections

Abstract

Abstract We present a theoretical analysis of the correlations between the macroscopic global transport properties and microscopic imperfections of a superlattice. High-field transport and domain formation is modelled using a microscopic quantum transport model which includes interface roughness and impurity scattering and describes resonant and nonresonant tunnelling processes in weakly coupled multiple quantum wells without adjustable parameters. Our analysis can be used on one hand to identify random fluctuations of the structural parameters in real samples like deviations from the perfect periodicity due to varying barrier widths, or doping densities in the individual wells. On the other hand, we demonstrate that the current–voltage characteristics can be tailored in a wide range to exhibit specific features like sharply rising steps at given voltages, arbitrarily modulated current maxima of multistable branches, or self-generated current oscillations.