Controlling interplay between weak localization and interface-roughness scattering of electrons in nonlinear transport within a superlattice

In this study, we have explored simultaneously two distinctive physical aspects of electron transport within a semiconductor superlattice subjected to both randomly distributed barrier scattering strengths and in-plane interface-roughness scattering of electrons within each barrier layer. To include interface-roughness scattering of electrons within a single barrier layer, we adopt the reduced Boltzmann transport equation to compute the nonequilibrium occupation function of electrons. In the presence of randomness within a superlattice, we apply a quantum-mechanical transfer-matrix approach for an electron wave to take into account all barrier-layer scattering within the superlattice. Consequently, the single-electron group velocity has been replaced by a mean group velocity assisted with a randomness-averaged transmission coefficient. For the interface-roughness scattering of electrons by each barrier layer, we numerically solve the reduced Boltzmann transport equation exactly and acquire the electrical current by another weighted average of obtained mean group velocities over the numerically calculated transient nonequilibrium occupation function of electrons from the reduced Boltzmann transport equation.