Electron states in metalized ultrathin film crystals and their thermodynamic behavior

Abstract

The dispersion law of electron in ultrathin crystalline metal-like film structures was found and analyzed using the method of two-time and temperature-dependent Green’s functions. Unlike unbounded (bulk) structures of the same crystallographic composition, the energy spectra of electrons in the film is strictly discrete, have two gaps and the narrower range of electron energies. Also, the conditions for the appearance and existence of localized electronic states as a function of boundary parameters were investigated. The probability of finding electrons in localized states is higher at more perturbed film boundaries. The electronic contribution to specific heat and entropy depends linearly on temperature, as in bulk structures, but with a different slope coefficient, so it follows that the electronic gas in films is a less ordered system and is closer to the equilibrium state than the same in bulk structures. These results could provide an explanation for the experimental facts about the stronger superconducting properties of ultrathin thin films.