Atomic structure of a long-range ordered vicinal surface of SrTiO3

We solved the structure of SrTiO3(106) by grazing incidence X-ray diffraction and direct methods. The surface exhibits SrO and TiO2 terminated half-steps, which are unstrained and the surface atoms are practically in their bulk-like positions. The resulting wavy surface exhibits an astonishing degree of long-range order, which is established by the alternating, weakly polar surface terminations. Since cation sites are partially occupied toward step edges, the surface is very smooth but lacks short-range order. This is very different from the behavior observed for metal and semiconductor surfaces, where stress resulting from short-range reconstruction is the driving force behind long-range order.