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

Stefan Gerhold; Zhiming Wang; Michael Schmid; Ulrike Diebold

doi:10.1016/j.susc.2013.10.015

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

Surf Sci. 2014 Mar;621(100):L1-L4. doi: 10.1016/j.susc.2013.10.015.

Authors

Stefan Gerhold¹, Zhiming Wang¹, Michael Schmid¹, Ulrike Diebold¹

Affiliation

¹ Institute of Applied Physics, Vienna University of Technology, Austria.

Abstract

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.

Keywords: Low energy electron diffraction; Low energy ion scattering; Scanning tunneling microscopy; Strontium titanate; Surface stoichiometry; X-ray photoelectron spectroscopy.