Defect evolution in oxide nanophases: The case of a zigzag-like TiOx phase on Pt(111)

The structure of a monolayer phase of TiOx on Pt(111) showing a zigzag-like contrast is investigated by scanning tunneling microscopy (STM) and density-functional calculations. Because of its peculiar defectivity, strongly dependent on the postdeposition thermal treatments, this system is an ideal model to study the structure and the evolution of defects in oxide nanophases. Atomistic models for each of the detected defects are obtained, which accurately reproduce the STM images showing that the experimentally observed defects essentially consist of Ti vacancies or irregular atomic distributions within the troughs exposing the bare substrate surface and that their formation energy is quite small, so that the system is under kinetic control in the given conditions of T and p(O2).