Existence of basal oxygen vacancies on the rutileTiO2(110)surface

Abstract

On a rutile ${\mathrm{TiO}}_{2}\phantom{\rule{0.16em}{0ex}}(110)$ surface, vacancies at the bridging oxygen sites are thought to be major surface point defects and strongly influence the surface phenomena. Using systematic density functional theory (DFT) calculations, however, we show that vacancies at the basal oxygen sites have comparable formation energies to the bridging oxygen vacancies. The correction of self-interaction error for localized $\mathrm{Ti}\phantom{\rule{0.16em}{0ex}}3d$ states in DFT plays an important role for correctly describing the relative stability of the oxygen vacancies as well as the electronic structures. This new type of stable surface oxygen vacancy can be formed with a similar amount of the bridging oxygen vacancy in a relatively dilute condition, which may affect atom deposition and chemical reactions on the surface.