The core structure of a screw dislocation in the diamond lattice was calculated using the Stillinger-Weber potential for interatomic interactions. The non-dissociated screw dislocation positioned at the centre of a unit hexagon normal to the dislocation line was a stable configuration (A). A perfect screw, centered on a longer edge of the unit hexagon, was also a stable configuration (B). The latter configuration was more stable, and had a lower energy than that of configuration-A. Dissociated configurations having a width, na (where a was the repeat distance in the slip direction and n was an integer), were also stable. The geometrical features of configuration-B explained the cross-slip which was observed in III-V compounds at low temperatures. The Peierls stress of the perfect screw dislocation was equal to 0.044G, where G was the shear modulus. This value corresponded to experimental values of III-V compounds which were deduced from the temperature-dependence of the critical shear stress at low temperatures.

Core Structure of a Screw Dislocation in a Diamond-Like Structure H.Koizumi, Y.Kamimura, T.Suzuki: Philosophical Magazine A, 2000, 80[3], 609-20