An ab initio estimate of correlation effects on the band gap of covalent semiconductors: diamond and silicon

An ab initio scheme, which has previously been used to determine electron-c orrelation effects on valence-band splittings in semiconductors, is extende d to yield the correlation-induced shift of the upper valence-band edge in diamond and silicon. Assuming that the processes of removing/adding one ele ctron from/to the solid causes symmetric correlation effects, this informat ion allows for an estimate of correlation contributions to band gaps. Reaso nable agreement with experiment is obtained. (C) 2000 Elsevier Science B.V. All rights reserved.