Ab initio derived augmented Tersoff potential for silicon oxynitride compounds and their interfaces with silicon

Coordination-dependent interatomic potentials are proposed for silicon oxides and oxynitrides-also hydrogenated ones-with a functional form based on the widely used Tersoff silicon potential. They are intended for an accurate sampling of the configurational space of realistic silicon oxynitride systems and their interfaces with silicon, including defects and changes of oxidation states. The parameters, which are given in the text, are obtained by simultaneously mapping forces and energies onto the results of density-functional-theory calculations performed for a set of diverse systems and configurations and a wide composition range. Application to a larger set of systems and configurations shows the transferability of these augmented Tersoff potentials and their validity in predicting bulk lattice parameters, energetics of defect relaxation, and vibrational spectra.