The effect of Ga impurities upon 90º Shockley partial dislocation was investigated by using first-principles total-energy pseudopotential calculations. The results indicated that the Ga segregated to the core of the dislocation and destabilized the asymmetrical 4-fold coordinated structure; which was known to be the low-energy configuration in the pure material. The segregation energy for Ga in the symmetrical core configuration was 0.53eV/atom. The atomic mechanism for this spontaneous transformation to the symmetrical structure involved the passivation, by Ga, of quasi 5-fold sites in the symmetrical core.

Structural transformation of the 90º partial dislocation in Si due to Ga impurities T.Kaplan, M.Mostoller, M.F.Chisholm: Physical Review B, 1998, 58[19], 12865-7