The atomic and electronic structures of a Σ3 (111) grain boundary were investigated by using first-principles band-structure total-energy/atomic-force methods within the local density approximation. The first-principles calculations revealed an expansion of the nearest Ti-Ti spacing across the grain-boundary plane, and a contraction of the nearest BaO-BaO spacing; in excellent agreement with experimental observations. An additional attraction of O atoms to the nearest Ti atom pairs, as well as a small volume expansion, were also found at the grain boundary. The atomic displacements were explained by means of an electronic structure analysis.

Atomic Displacements at a Σ3 (111) Grain Boundary in BaTiO3 - a First-Principles Determination. W.T.Geng, Y.J.Zhao, A.J.Freeman, B.Delley: Physical Review B, 2001, 63[6], 060101 (4pp)