Projector augmented-wave approach to density-functional perturbation theory

Abstract

The density-functional theory total energy within the projector-augmented wave formalism is expressed in a form suitable for application of the variation-perturbation formalism. We derive the corresponding expressions up to the third order. The much deeper complexity of the projector-augmented wave formalism, compared to the norm-conserving pseudopotential case, implies the introduction of several new notations. However, the structure of the resulting formalism is quite similar, and should be as useful, accurate, and widely applicable.