Stress-Driven Reconstruction of an Oxide Surface: The AnataseTiO2(001)−(1×4)Surface

Abstract

The recently discovered ( $1\times 4$) reconstruction of the stoichiometric anatase ${\mathrm{TiO}}_2\left(001\right)$ surface is studied via first principles density functional calculations. We propose a new structural model for this reconstruction, which is energetically much more favorable than all the other available models, including the unreconstructed ( $1\times 1$) surface. In this model, rows of ${\mathrm{TiO}}_3$ species periodically replace rows of surface bridging oxygens of the ( $1\times 1$) surface, thus leading to a relief of the large surface tensile stress present on that surface. The corresponding empty-state charge density distribution correctly describes the experimental scanning tunneling microscopy images.