LEED-IV study of the rutile TiO2(110)-1x2 surface with a Ti-interstitial added-row reconstruction

Upon sputtering and annealing in UHV at similar to 1000 K, the rutile TiO2(110) surface undergoes a 1x1 -> 1x2 phase transition. The resulting 1x2 surface is Ti rich, formed by strands of double Ti rows as seen on scanning tunneling microscopic images, but its detailed structure and composition have been subject to debate in the literature for years. Recently, Park [Phys. Rev. Lett. 96, 226105 (2006)] have proposed a model where Ti atoms are located on interstitial sites with Ti2O stoichiometry. This model, when it is analyzed using LEED-IV data [Phys. Rev. Lett. 96, 0055502 (2006)], does not yield an agreement between theory and experiment as good as the previous best fit for Onishi and Iwasawa's model for the long-range 1x2 reconstruction. Therefore, the Ti2O3 added row is the preferred one from the point of view low-energy electron diffraction.