A study was made of the structural features and formation energies of a/3<112> kinks in a/2<111> screw dislocations with various core structures. A family of embedded atom model potentials for Ta was used, all of which reproduced the bulk properties (density, cohesive energy, elastic constants), but which differed with respect to the resultant polarization of a/2<111> screw dislocations. For dislocations with an asymmetrical core, there were 2 energy-equivalent core configurations (with positive and negative polarization) which led to 2 types of (polarization) flip, 8 kinds of isolated kink and 16 combinations of kink pairs. It was found that there were only 2 elementary kinks, while the others were composites of elementary kinks and flips. For screw dislocations with a symmetrical core, there were only 2 types of isolated kink and one kind of kink pair. It was found that the equilibrium dislocation core structure of a/2<111> screw dislocations was an important factor in determining the kink-pair formation energy.

Atomistic Simulations of Kinks in 1/2a<111> Screw Dislocations in BCC Tantalum. G.Wang, A.Strachan, T.Çağın, W.A.Goddard: Physical Review B, 2003, 68[22], 224101 (15pp)