Total-energy electronic structure calculations were performed for mono-, di- and multi-vacancies within the local density approximation of density functional theory. It was shown that covalency, elasticity and electron correlation each played its own role in determining the atomic structures and resultant electron states which were caused by these imperfections in perfect covalent semiconductors.

A.Oshiyama, M.Saito, O.Sugino: Applied Surface Science, 1995, 85, 239-45