Correlation between surface rumpling and structural phase transformation of SrTiO3

We present x-ray reflectivity, x-ray diffraction and atomic force microscopy measurements of single crystal SrTiO3 taken as a function of temperature. We found a rumpling transformation of the SrTiO3 surface after cooling the sample below ~105 K. The rumpling transformation is correlated with the cubic to tetragonal phase transformation that occurs at the same temperature. The rumpling transformation is reversible.