Disorder Induced e-h Correlation in Photoexcited Transients in Semiconductors

Abstract

In mixed semiconductor crystals, the alloy disorder in the valence and conduction bands is statistically correlated. This leads to kinematical correlations in the motion of electrons and holes analogous to exciton effects. This mechanism long known to affect the linear optical response is presently shown to act also in the non-linear regime induced by strong short light pulses. A direct numerical solution of the Kadanoff—Baym equations for non-equilibrium Green functions (employing a self-consistent and conserving single-site approximation) is used to demonstrate the onset and a ripe stage of correlations between the electron and hole photoexcited populations, and the influence of the transient light induced band hybridization.