Ab initio method for excited states in solids: correlation corrections to the band structure of oxides

A new ab initio wave-function based method to study the electron correlation effects on band structures of oxide systems is presented here. It is based on the "simplified method" first introduced by Fulde and Stoll [Theor. Chem. Acc. 116 (2006) 398-403] and analyzed in more detail by Pahl and Birkenheuer [J. Chem. Phys. 124 (2006) 214101]. Bulk MgO is chosen as a prototype closed-shell ionic oxide, a realistic but at the same time still relatively simple insulating system, to prove the abilities of that new approach. We will identify the major correlation induced corrections to the valence and conduction bands of MgO and the closing of the Hartree-Fock band gap due to electron correlation.