Application of the Spectral Density Method to the Anderson-Holstein Model

Two-parameter spectral density function (density of states) of a magnetic impurity electron in a non-magnetic metal is calculated using a single-level Anderson-Holstein model using the spectral density method. Here we have treated electron-electron interaction within the mean-field level and investigated the effect of electron-phonon interaction on the spectral function. We have observed a strong polaronic effect with increasing electron-phonon interaction strength at zero temperature.