The energetics of the single-period and double-period core reconstructions of the 90º partial dislocation were investigated. The double-period geometry was found to be lower in energy, and the energy difference between the 2 geometries was shown to follow the same trends as the energy-gap and the stiffness. Both structures were fully reconstructed, and consisted entirely of 4-fold coordinated atoms. They differed mainly with regard to the details of the local strains that were introduced, by the 2 reconstructions, into the core region. The double-period structure was shown to introduce smaller average bond-length deviations, at the expense of slightly larger average bond-angle bending distortions, with respect to the single-period core. The balance between these 2 strain components led to a lower energy for the double-period reconstruction.

Core reconstruction of the 90° partial dislocation in non-polar semiconductors R.W.Nunes, J.Bennetto, D.Vanderbilt: Physical Review B, 1998, 58[19], 12563-6