Theoretical calculations of the structure, formation, and migration of kinks on a non-dissociated screw dislocation in Si were carried out using density functional theory calculations as well as calculations based upon interatomic potential functions. The results showed that the structure of a single kink was characterized by a narrow core and highly stretched bonds between some of the atoms. The formation energy of a single kink ranged from 0.9 to 1.36eV, and was of the same order as that for kinks on partial dislocations. However, the kinks migrated almost freely along the line of an undissociated dislocation; contrary to that found for partial dislocations. The effect of stress was also investigated for comparison with previous Si deformation experiments which had been carried out at low temperatures and high stresses. The energy barrier associated with the formation of a stable kink pair became as low as 0.65eV for an applied stress of the order of 1GPa; indicating that displacements of screw dislocations probably occurred via the thermally activated formation of kink pairs at room temperature.

Theoretical Study of Kinks on Screw Dislocation in Silicon. L.Pizzagalli, A.Pedersen, A.Arnaldsson, H.Jónsson, P.Beauchamp: Physical Review B, 2008, 77[6], 064106 (14pp)