Surface reconstructions of TiO2(110) driven by suboxides

Scanning tunneling microscopy and density functional theory are used to develop a new structural model for surface reconstructions driven by Ti interstitials on TiO2(110). Ti interstitials form the edge- or face-sharing octahedra that serve as building blocks for (1 x 1) reconstruction. Thus, contrary to conventional wisdom, the 1 x 1 periodicity is insufficient to establish the correct surface stoichiometry. Furthermore, in our structural and compositional model the reversible oxidation or reduction between (1 x 1) and (1 x 2) is entirely achieved by transfer of the added rows.