Study of the surface dielectric function: toward screening field effects in optical nonlinearities

A large number of works have been dedicated to the studies of the optical responses of metallic surfaces in the framework of the Jellium model. However, because this model is one dimensional, the fundamental problem of the polarization and azimuthal anisotropies cannot be handled. In the present description, by using a band model going beyond the nearly free electron model, the anisotropy properties are preserved in the description of the surface screening due to the Coulomb interaction. This enables us to evaluate the frequency and wave vector dependence of the dielectric function required in further studies of nonlinear optical responses of surfaces where anisotropies are experimentally observed. Here, the dielectric function of the Al(1 1 1) surface is explicitly calculated.