Oxygen-induced broken-bond defect in silicon

The electronic and geometric structure of a recently proposed oxygen-related defect in silicon is studied using a precise Iab initioP quantum-molecular-dynamics method based on local-density-functional theory, nonlocal pseudopotentials, and the supercell approximation. This defect is a metastable configuration of interstitial oxygen in Si (Si:${\mathrm{O}}_{\mathit{i}}$), and it is closely related to a vacancy-interstitial pair. This defect has a relatively low formation energy despite the presence of a silicon broken bond. A simple and straightforward procedure is used to identify the static barrier for the formation of an intimate vacancy-interstitial pair in silicon and the static barrier for the recombination of the broken bond in metastable Si:${\mathrm{O}}_{\mathit{i}}$. The similarities in geometric configurations for both cases are explored to introduce a mechanism for the creation of intimate vacancy-interstitial-like defects in silicon.