The electronic structure of SiO2, GeO2 and intermediate SixGe1−xO2 compositions: experiment and theory

Theoretical calculations are reported for SiO₂, GeO₂ and the intermediate composition Si_.5Ge_.5O₂ which reproduce the main observed features and trends in experimental photoemission spectra. The agreement between the two establishes the importance of band theory in understanding the electronic structure of these materials, and demonstrates that detailed quantitative predictions are feasible for such complex materials in terms of the empirical tight-binding method. The calculations further establish that the structure in the valence bands is determined mainly by nearest- neighbor oxygen-oxygen interactions.