Core polarization in semiconductors: Effects on quasiparticle energies

We study core-valence interactions in several technologically important semiconductors. We compute band structures treating many-body effects in Hedin's GW approximation. The core-valence correlation and core polarization are treated using a core-polarization potential formulation instead of standard, less reliable, mean-field approaches. This is critical for materials with shallow cores (Ge, GaAs), where mean-field treatments of core-valence interactions bias certain band gaps by up to 0.4 eV. The core-polarization potential formulation may be used in either frozen-core all-electron or pseudopotential calculations, since it deals only with core-valence many-body effects.