Density functional theory study of point defects in the Si-SiO2 system and in substoichiometric titanium dioxide TiO2-x

Density functional theory allows us now to calculate structural and energetic quantities related to nonstoichiometric oxides. Using as examples solutions of oxygen in silicon, substoichiometric titanium dioxide TiO2-x, and vacancies in silica, we show that, despite severe requirements in terms of computational effort, these calculations give insights into the nature of defects and their contribution to the macroscopic properties of nonstoichiometric oxides. (C) 2003 Wiley Periodicals, Inc.