It was suggested that the usually accepted core structure for the 90° partial dislocation in Si might be correct. A period-doubled structure was proposed instead. Local-density approximation, tight-binding, and classical Keating-model calculations all indicated that the period-doubled structure was lower in energy. The new structure exhibited a broken mirror symmetry, in addition to the period-doubling. This led to a wide range of possible soliton-like defects and kinks.

J.Bennetto, R.W.Nunes, D.Vanderbilt: Physical Review Letters, 1997, 79[2], 245-8