Transition from reconstruction toward thin film on the (110) surface of strontium titanate

Z. Wang, A. Loon, A. Subramanian, S. Gerhold, E. McDermott, J. A. Enterkin, M. Hieckel, B. C. Russell, R. J. Green, A. Moewes, J. Guo, P. Blaha, M. R. Castell, U. Diebold, L. D. Marks

Institut für Angewandte Physik, TU Wien, 1040 Wien, Austria
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, U.S.A.
Institute of Materials Chemistry, TU Wien, Getreidemarkt 9/165-TC, 1060 Vienna, Austria
Department of Chemistry, Northwestern University, Evanston, Illinois 60208, U.S.A.
Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom
Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2, Canada

Nano Lett. 16 (2016) 2407-2412

The surfaces of metal oxides often are reconstructed with a geometry and composition that is considerably different from a simple termination of the bulk. Such structures can also be viewed as ultrathin films, epitaxed on a substrate. Here, the reconstructions of the SrTiO3(110) surface are studied combining scanning tunneling microscopy (STM), transmission electron diffraction, and X-ray absorption spectroscopy (XAS), and analyzed with density functional theory calculations. Whereas SrTiO3(110) invariably terminates with an overlayer of titania, with increasing density its structure switches from n × 1 to 2 × n. At the same time the coordination of the Ti atoms changes from a network of corner-sharing tetrahedra to a double layer of edge-shared octahedra with bridging units of octahedrally coordinated strontium. This transition from the n × 1 to 2 × n reconstructions is a transition from a pseudomorphically stabilized tetrahedral network toward an octahedral titania thin film with stress-relief from octahedral strontia units at the surface.

Corresponding author: Zhiming Wang. Reprints also available from Ulrike Diebold (diebold at iap_tuwien_ac_at).

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