The energies of point defects in graphite were calculated from first principles. The various interplane interstitial configurations were found to have a wider range of energies than in some earlier calculations, implying a larger interstitial migration energy than previously expected (>1.5eV). Interplane interstitials were found to be stabilized by a shear of one graphite plane with respect to its neighbors, as this allowed the interstitial to bond to 3 or 4 atoms in 2 planes in 2 configurations. The minimum interstitial formation energy in sheared graphite was only 5.3eV, compared to 6.3eV in perfect graphite. Such interstitials formed a strongly bound vacancy-interstitial pair with a formation energy of only 10.2eV. The formation energy of a single vacancy was 7.6eV. The formation energy and the activation barrier of the Stone-Wales defect in a single layer of graphite were also calculated.

Defect Energies of Graphite - Density-Functional Calculations. L.Li, S.Reich, J.Robertson: Physical Review B, 2005, 72[18], 184109