Mixed-basis pseudopotential method applied to iterative diagonalization techniques

We apply a mixed-basis formulation of pseudopotential total-energy electronic structure calculations in the context of iterative diagonalization techniques. The formulation combines a small set of auxiliary functions to describe the localized part of the wave function with a plane-wave basis set. The method is tested on low-symmetry configurations of interstitial oxygen in silicon. This method provides accuracy comparable to plane-wave basis-set calculations and requires less computational effort. Therefore, it appears to be a promising tool for the description of the electronic structure of systems with localized valence electrons.