On the influence of a smooth gaussian random field on optical thresholds in disordered semiconductors and external electric field induced change

Abstract

AbstractThe interband dielectric function ϵ(ω) and its external field induced change Δϵ(ω, E) are calculated in the one‐electron approximation for optical transitions between initial and final states shifted randomly in space by a smooth Gaussian random field. All types of critical points are considered. Using an exact semi‐classical approach up to the order of h2 the influence of the smooth Gaussian random field in ϵ(ω) and Δϵ(ω, E) is shown to be representable as an averaging of the corresponding Franz‐Keldysh expressions. The M3 and M2 problems are shown to be reducible to the M0 and M1 ones. The plots for ϵ(ω) and Δϵ(ω. E) are presented for the isotropic M0 point and the M1 point with equal transversal masses.