Density of States in Multilayer Sandwiches

Abstract The density of states of finite metal—semimetal system is considered in the case of boundary conditions that assure the damping of electronic states at infinity. The density of states of the transition region metal‐semimetal is investigated which is found to be strongly dependent on the shape of the transition layer. Special attention is paid to the case when in one part of the system, in the metal, the coherence of the motion of the electron is broken, while in the other part, in the semimetal, the electron moves coherently. Under this condition, the oscillations of the density of states of systems consisting of a metallic film covered on both sides with the semimetal, and systems consisting of two metallic films with a semimetallic interlayer are considered. Within the model described, one can understand the experimentally observed behaviour of Tc (the temperature of the superconducting transition) at small thicknesses of the semimetallic layer.