Correlation between surface rumpling and structural phase transformation in 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 similar to 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.