The structure of an isolated, Ga terminated, 30° partial dislocation in GaAs:Be was determined by high resolution transmission electron microscopes and focal series reconstruction. The positions of atomic columns in the core region were measured to an accuracy of better than 10pm. A quantitative comparison of the structure predicted by an ab initio electronic structure total energy calculation to the experiment indicated that theory and experiment agree to within 20pm. Further analysis showed the deviations between theory and experiment appear to be systematic. Electron energy loss spectroscopy establishes that defects segregate to the core region, thus accounting for the systematic deviations.

Distortion and Segregation in a Dislocation Core Region at Atomic Resolution. X.Xu, S.P.Beckman, P.Specht, E.R.Weber, D.C.Chrzan, R.P.Erni, I.Arslan, N.Browning, A.Bleloch, C.Kisielowski: Physical Review Letters, 2005, 95[14], 145501 (3pp)