The geometry and atomic structure of the mechanical twin boundary in LiNbO_3 have been investigated. A possible structural model of this mechanical twin is derived and compared with the observed structure. The structure of the mechanical twin in stoichiometric LiNbO_3 is coherent and its composition plane is one of the {012} planes. This mechanical twin can be explained by a twin model of slip between the two Nb-centred octahedral layers and a slight distortion of each octahedron.
展开▼
