X-ray diffraction data denying the hypothesis of surface D4hin SrTiO3

Abstract
Peak profiles of the high-angle double-crystal X-ray diffraction (HADOX) of SrTiO3 have been examined around the structural phase transition at 105K. There is no indication of the existence of surface D4h layers above the transition, in spite of high resolution of the experiment. The peak width of a monodomain region shows a critical behaviour, which, as a function of temperature, does not depend on the depth from the specimen surface, 1 to 57 mu m. The hypothesis of a depth-dependent transition can also be excluded by this fact.