Formation energies, binding energies, structure, and electronic transitions of Si divacancies studied by density functional calculations

Abstract

Atomic configurations, formation energies, electronic transition energies, and binding energies of the silicon divacancy in the $+1$, $0$, $\ensuremath{-}1$, and $\ensuremath{-}2$ charge states were obtained from density functional theory calculations. The calculations were performed using the local density approximation (LDA) and also the Perdew, Burke, Ernzerhof (PBE) formulation of the generalized-gradient approximation. Supercells of nominally 216, 512, and 1000 atoms were used to extrapolate formation energies for infinite-sized supercells corresponding to isolated defects. The predicted ground-state configuration was found to depend on charge state and the chosen formulation of exchange and correlation (LDA or PBE). Structures, binding energies, and transition energies are compared to values reported in the literature.