The free energy of a new structure for the core of the 90º partial dislocation, which exhibited twice the crystal periodicity along the dislocation line, was found to differ insignificantly from that for the previously accepted single-crystal period core-structure at temperatures where dislocations became mobile. It was therefore proposed that both core structures existed. It was noted that, although it was theoretically possible to distinguish between these core structures by using 400kV high-resolution electron microscopy, the published experimental images were unable to distinguish between the competing core structures.

The core reconstruction of the 90º partial dislocation in silicon A.Valladares, A.K.Petford-Long, A.P.Sutton: Philosophical Magazine Letters, 1999, 79[1], 9-17