A Theory of Dynamical Responses for Metal Films: Surface Roughness Effects

Abstract

A generic expression is derived for the dynamical response function of metal films, with conductivity tensors as the only input. The semi-classical model is then used to provide an analytical expression for the conductivity tensor, thus establishing a kinetic theory for the response function. A major advantage of the theory is its ability to handle surface roughness effects through the use of the so-called specularity parameter. We applied the theory to study the properties of surface plasma waves. It is found that surface roughness does not affect the dispersion, but rather the decay rate of these waves. Furthermore, it significantly affects the spectral weight carried by the SPW resonances, which diminishes toward zero as the specularity parameter approaches unity.