The effects of As on the properties of dislocations in Si were studied. The theoretical investigation was carried out by using ab initio total energy methods, based upon density functional theory. It was found that the interaction of an As impurity in the crystal with a dislocation results in a charge exchange, driving the dislocation core to a negative charge state. This interaction was essentially electrostatic and attractive, and led to As segregation. Although As segregation to the core was energetically favourable, formation of As pairs within the core was energetically unfavourable. The role played by vacancies in As diffusion within the dislocation core was also investigated.

Arsenic Segregation, Pairing and Mobility on the Cores of Partial Dislocations in Silicon. A.Antonelli, J.F.Justo, A.Fazzio: Journal of Physics - Condensed Matter, 2002, 14[48], 12761-5