The structure and energies of formation of antiphase defects on the single period (SP) 90° partial dislocation in Si were studied by using a first-principles density functional method. Two types of antiphase defect were considered: a type, first proposed by Hirsch, wholly inside the dislocation core and another type that lay partly outside the core. Both types were stable and contained one atom which was threefold coordinated. Each of these atoms has a dangling hybrid which lay in a direction perpendicular to the dislocation line on the slip plane. Values of 1.39 and 1.41eV were obtained for the average formation energy of single antiphase defects of the inside and outside types, respectively. Using a tight binding scheme, band-structures were obtained which corresponded to these 2 types of defect, and both of them were found to be associated with states in the gap; with each dangling hybrid containing one electron.First-Principles Simulations of Antiphase Defects on the SP 90° Partial Dislocation in Silicon. A.Valladares, A.P.Sutton: Journal of Physics - Condensed Matter, 2006, 18, 3735-44