Formation and annihilation of a bond defect in silicon: An ab initio quantum-mechanical characterization

The electronic structure and bond properties of a lattice defect in silicon formed by the incomplete recombination of a vacancy-interstitial pair are described by combining tight-binding molecular-dynamics and ab initio Hartree-Fock calculations. The defect structure consists of a large nuclear distortion nearly perfectly compensated by electron charge rearrangment. The reaction path for its annihilation is reported and described in terms of an electron-density topological analysis within the quantum theory of atoms in molecules approach.