The 2 × 1 reconstruction of the rutile TiO2(011) surface: A combined density functional theory, X-ray diffraction, and scanning tunneling microscopy study

X.-Q. Gong, N. Khorshidi, A. Sierle, V. Vonk, C. Ellinger, H. Dosch, H. Cheng, A. Selloni, Y. He, O. Dulub, U. Diebold

Labs for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai 200237, PR China
Max-Planck-Institut für Metallforschung, D-70569 Stuttgart, Germany
Department of Chemistry, Princeton University, Princeton, New Jersey 08544, U.S.A.
Department of Physics, Tulane University, New Orleans, Louisiana 70118, U.S.A.

Surf. Sci. 603 (2009) 138-144

An extensive search for possible structural models of the (2 × 1)-reconstructed rutile TiO2(011) surface was carried out by means of density functional theory (DFT) calculations. A number of models were identified that have much lower surface energies than the previously-proposed 'titanyl' and 'microfaceting' models. These new structures were tested with surface X-ray diffraction (SXRD) and voltage-dependent STM measurements. The model that is (by far) energetically most stable shows also the best agreement with SXRD data. Calculated STM images agree with the experimental ones for appropriate tunneling conditions. In contrast to previously-proposed models, this structure is not of missing-row type; because of its similarity to the fully optimized brookite TiO2(001) surface, we call it the 'brookite (001)-like' model. The new surface structure exhibits two different types of undercoordinated oxygen and titanium atoms, and is, in its stoichiometric form, predicted to be rather inert towards the adsorption of probe molecules.

Reprints available from U. Diebold (diebold at iap_tuwien_ac_at).

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