A density functional plane-wave pseudopotential method was used to study various Σ = 5 (001) twist boundary models for strontium titanate. Results concerning the atom-level geometries and electronic structures were reported. The structures had varying SrO/TiO2 ratios and their relative stabilities were explained in terms of the SrO chemical potential. A twist boundary containing a Sr-O pair of vacancies was found to be exceptionally stable and had a low volume expansion and was a possible candidate for showing impurity segregation.

A Computational Study of Twist Boundary Structures in Strontium Titanate. R.Astala, P.D.Bristowe: Journal of Physics - Condensed Matter, 2002, 14[49], 13635-41