GENERALIZED PLASMON-POLE MODEL AND PLASMON BAND STRUCTURES OF CRYSTALS

A generalized plasmon-pole model is presented to describe the energy d ependence of the polarizability of semiconductors and insulators. This model leads in a natural way to a simple prescription for determining plasmon band structures. As an application, the plasmon band structur e of silicon is calculated within the random-phase approximation. Our plasmon-pole model offers considerable computational advantages over e arlier such models in the context of self-energy calculations within t he Hedin GW framework. Furthermore, we comment on the purely classical origin of the f-sum rule for the polarizability.