Calculation of the electronic energy spectrum of a thin disordered solid film

Abstract

AbstractThe effects of positional disorder on the electronic energy spectrum of a model finite insulating barrier are considered. The spectrum is studied for two different sets of boundary conditions imposed at the film surfaces: 1) traveling wave boundary conditions, leading to transmission resonances, and 2) periodic boundary conditions. Ledermann's theorem relates the transmission resonances to the corresponding discrete spectrum obtained using periodic boundary conditions. Halpern's reduced Green function technique for the calculation of approximate spectra of infinite systems is extended from a single to a multiband formulation and applied to the thin film problem. A quantitative estimate of the effect of the loss of short range order on the integrated density of states in a thin film is presented. The spectrum is discussed and related to the elastic tunneling transmission coefficient of a metal–insulator–metal heterojunction in which the insulating film is the tunneling barrier.