X-ray surface diffraction analysis of structural transformations on the (0 0 1) surface of oxidized SrTiO₃

Surface X-ray scattering was used to study structural modifications on the (0 0 1) surface of oxidized SrTiO₃. Grazing incidence in-plane X-ray diffraction revealed a sequence of quasi-powder diffraction peaks originating from crystallites with nearly random in-plane orientation. This diffraction pattern is associated with micro-crystallites of irregular shape observed by atomic force microscopy on the surface after annealing in oxygen. Analysis based on available powder diffraction data identified these crystallites as monoclinic TiO. Different oxygen annealing treatments led to dramatic changes in the specular (0 0 L) crystal truncation rods indicating significant structural modifications in the underlying single crystal SrTiO₃ surface layer.