The stability of the perfect screw dislocation in Si was investigated using both classical potentials and first-principles calculations. Although a recent study had concluded that the stable screw dislocation was located in both the shuffle and the glide sets of {111} planes, it was shown that this result depended upon the classical potential used, and that the most stable configuration belongs to the shuffle set only; in the center of one (¯101) hexagon. The stability of an sp2 hybridization in the core of the dislocation, obtained for one metastable configuration in the glide set, was also investigated. The core structures were characterized in several ways, with a description of the 3-dimensional structure, differential displacement maps and derivatives of the disregistry.

Undissociated Screw Dislocations in Silicon - Calculations of Core Structure and Energy. L.Pizzagalli, P.Beauchamp, J.Rabier: Philosophical Magazine, 2003, 83[10], 1191-20