Dislocations in diamond: Core structures and energies

The structures and core energies of dislocations in diamond are calculated using both isotropic and anisotropic elasticity theory combined with ab initio-based tight-binding total energy calculations. Perfect and dissociated 60degrees and screw dislocations are considered. Their possible dissociation reactions are investigated through a consideration of the calculated elastic energy factors and core energies. Dissociation into partials is energetically favored. We find that the double-period reconstruction of the 90degrees glide partial dislocation is more stable than the single-period reconstruction and that the glide set of 60degrees perfect dislocations is more stable than the shuffle set. Shuffle partials containing interstitials are less likely than those containing vacancies.