Generalized plasmon-pole model and plasmon band structures of crystals

A generalized plasmon-pole model is presented to describe the energy dependence 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 structure of silicon is calculated within the random-phase approximation. Our plasmon-pole model offers considerable computational advantages over earlier such models in the context of self-energy calculations within the Hedin GW framework. Furthermore, we comment on the purely classical origin of the f-sum rule for the polarizability.