Density functional super-cell calculations were carried out by applying a mixed-basis pseudopotential method to the Σ3 (111)[1¯10] symmetrical tilt grain boundary; as a prototype planar defect in an electroceramic material. A grain boundary energy of only 0.52J/m2 was predicted. Minor structural relaxations from the coincidence site lattice model were found close to the grain boundary plane. Within the limits of this relatively small super-cell model, the calculated geometrical structure agreed well with the experimentally observed one. An analysis of the calculated local electron densities of states showed that the perturbation which was due to the grain boundary was localized to the near vicinity of the boundary plane. On the basis of the present results for the small super-cell model, there was no evidence for the build-up of a space-charge layer at this highly-ordered and undoped twin boundary.

Density Functional Study of the Σ3 (111) [1¯10] Symmetrical Tilt Grain Boundary in SrTiO3. S.Hutt, S.Köstlmeier, C.Elsässer: Journal of Physics - Condensed Matter, 2001, 13[18], 3949-60