Nanostructure of a vicinal surface ofSrTiO3: Order on two length scales

Abstract

Grazing incidence x-ray diffraction, combined with low energy electron diffraction and scanning tunneling microscopy shows that annealed ${\mathrm{SrTiO}}_{3}(103)$ surfaces exhibit regular nanostructures on two length scales with shorter $(\ensuremath{\sim}1.2\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ ripples bunching to longer $(\ensuremath{\sim}7.4\phantom{\rule{0.3em}{0ex}}\mathrm{nm})$ waves, corresponding to six ${\mathrm{SrTiO}}_{3}(103)$ unit cells. The surface, wavy in the [100] direction, exhibits $\mathrm{SrO}$ and ${\mathrm{TiO}}_{2}$ terminated ``steps.'' Lateral relaxations along the [010] direction of the unit cell lead to a weak $(1\ifmmode\times\else\texttimes\fi{}2)$ reconstruction. Electrostatic forces are thought to be responsible for the observed surface morphology.