Dynamical Response and Surface Excitations in Thin Films

Abstract

The non-local dynamically screened Coulomb interaction propagator W(Q, z, z', ω) in the vicinity of thin metal film is calculated for points inside and outside of the film, taking both collective modes and single-particle excitations into account. This is achieved by calculating the non-local dielectric function ϵp(Q, z, z', ω) of the thin jellium film within the Random Phase Approximation (using Local Density Approximation wave-functions), from which we then derive W(Q, z, z', ω). The calculated dielectric function is also used to obtain excitation spectra, and specifically dispersion relations of the collective modes.