Stoichiometry-driven switching between surface reconstructions on SrTiO3(001)

S. Gerhold, Z. Wang, M. Schmid, U. Diebold

Institut für Angewandte Physik, Technische Universität Wien, 1040 Wien, Austria

Surf. Sci. 621 (2014) L1-L4

Controlling the surface structure on the atomic scale is a major difficulty for most transition metal oxides; this is especially true for the ternary perovskites. The influence of surface stoichiometry on the atomic structure of the SrTiO3(001) surface was examined with scanning tunneling microscopy, low-energy electron diffraction, low-energy He+ ion scattering (LEIS), and X-ray photoelectron spectroscopy (XPS). Vapor deposition of 0.8 monolayer (ML) strontium and 0.3 ML titanium, with subsequent annealing to 850 °C in 4 × 10-6 mbar O2, reversibly switches the surface between c(4 × 2) and (2 × 2) reconstructions, respectively. The combination of LEIS and XPS shows a different stoichiometry that is confined to the top layer. Geometric models for these reconstructions need to take into account these different surface compositions.

Corresponding author: Ulrike Diebold (diebold at iap_tuwien_ac_at).

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