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O: Fachverband Oberflächenphysik

O 31: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I

O 31.8: Vortrag

Dienstag, 21. März 2017, 12:15–12:30, WIL C107

Ordered structures in reduced SrTiO₃ on Pd(111) — •Bettina Leibundgut¹, Stefan Förster¹, and Wolf Widdra^1,2 — ¹Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — ²Max Planck Institute of Microstructure Physics, Halle, Germany

Ultrathin perovskite films exhibit extraordinary complex structures on Pt(111) in the two-dimensional limit. Upon reduction by UHV annealing, two-dimensional oxide quasicrystal or closely related periodic approximant structures have been reported for BaTiO₃ and SrTiO₃ on Pt(111) [1-3]. Here we report on the formation of similarly complex structures from SrTiO₃ on Pd(111). The films are grown by reactive molecular beam epitaxy from a Nb-doped SrTiO₃ single crystal and a Ti rod. For Ti rich growth conditions, a phase separation in TiO_x and SrO occurs upon annealing at 950 K. This is deduced from SPALEED observation of the rectangular phase of reduced TiO_x on Pd(111), which is well-known for Pt(111) [4]. When approaching stoichiometric SrTiO₃ films, several large unit cell superstructures are observed, that will be discussed with respect to aperiodic structures.
S. Förster K. Meinel, R. Hammer, M. Trautmann, W. Widdra, Nature 502, 215 (2013) [2] S. Förster et al., Phys. Rev. Lett. 117, 095501 (2016) [3] S. Schenk et al., submitted to J. Phys: Condens. Matter [4] F. Sedona et al., J. Phys. Chem. B 7, 697 (2005).