The atomic structure of a multiple-twin lamella junction in a film sample was investigated by means of high-resolution electron microscopy. The investigation was not based upon the direct study of experimental micrographs, but upon a study of the quantum-mechanical electron wave-function which emerged from the object. The electron wave-function was obtained by means of numerical reconstruction procedures which were based on a series of high-resolution micrographs which had been taken from the same area, using different settings of the objective lens de-focus. Within the observed junction area 4 types of twin variant, including 2 groups of nano-twins, meet each other. This resulted in a complicated boundary structure with a mixture of S = 27 and S = 3 segments. This junction was regarded as being a grain boundary which connected 2 hexagonal structure domains that were composed of 2 groups of nano-twins. A boundary structure unit was identified, in which some of the BaO [110] columns were found to be partially occupied.

Atomic Structure of a Σ = 3, {111} Twin-Boundary Junction in a BaTiO3 Thin Film. C.L.Jia, R.Rosenfeld, A.Thust, K.Urban: Philosophical Magazine Letters, 1999, 79[3], 99-106