Model calculations of local electron and phonon densities of states in bimetallic superlattices

Publisher Website
Google Scholar
Abstract
We have analytically obtained the exact Green's functions for electrons and phonons in a bimetallic superlattice. The electrons are treated in the tight-binding approximation, and the phonons are of one acoustic branch in a lattice with nearest-neighbor coupling. The most interesting effects arise near the interfaces when the acoustical or electronic coupling between layers is large compared to the intralayer coupling. In this large coupling case, the local phonon density of states at low frequency is enhanced by a linear contribution due to interface modes. The appearance of electronic interface states in the local density of states is discussed. The impact of our results on superconducting properties is considered. The influence of zone-folding effects is found to be small.