Atomic-scale visualization of initial growth of homoepitaxial SrTiO₃ thin film on an atomically ordered substrate.

The initial homoepitaxial growth of SrTiO(3) on a (√13 × √13)-R33.7° SrTiO(3)(001) substrate surface, which can be prepared under oxide growth conditions, is atomically resolved by scanning tunneling microscopy. The identical (√13 × √13) atomic structure is clearly visualized on the deposited SrTiO(3) film surface as well as on the substrate. This result indicates the transfer of the topmost Ti-rich (√13 × √13) structure to the film surface and atomic-scale coherent epitaxy at the film/substrate interface. Such atomically ordered SrTiO(3) substrates can be applied to the fabrication of atom-by-atom controlled oxide epitaxial films and heterostructures.