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O: Fachverband Oberflächenphysik
O 92: Gerhard Ertl Young Investigator Award
O 92.2: Vortrag
Donnerstag, 23. März 2017, 11:00–11:30, TRE Ma
Fascinating two-dimensional oxide quasicrystals — •Stefan Förster1, Sebastian Schenk1, Klaus Meinel1, Eva Maria Zollner1, Rene Hammer1, and Wolf Widdra1,2 — 1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — 2Max Planck Institute of Microstructure Physics, Halle, Germany
When approaching the two-dimensional limit, oxides are known to exhibit strong variations in their structures and properties as compared to the respective bulk materials[1]. One of the best examples are the two-dimensional oxide quasicrystals (OQCs), which have been discovered for reduced BaTiO3 on Pt(111) [2]. We report here on a second OQC derived from SrTiO3 on Pt(111) as well as on approximant structures for both OQC systems, in which selected motifs of the OQC are periodically repeated. Those approximants differ drastically in their complexity. For BaTiO3 a simple approximant structure is observed, which contains six of the building blocks (tiles) of the OQC in the unit cell and which has been structurally fully resolved recently [3]. For SrTiO3 the more complex approximant contains a patch of 36 tiles in the unit cell. This approximant very closely resembles the ideal OQC. Our studies unravel OQCs as best-controlled QC model systems for addressing the fundamental questions related to the driving forces for aperiodic structure formation.
[1] F. Netzer, S. Fortunelli (Eds.), Oxide Materials at the two-dimensional limit, Springer (2016) [2] S. Förster K. Meinel, R. Hammer, M. Trautmann, W. Widdra, Nature 502, 215 (2013) [3] S. Förster et al., Phys. Rev. Lett. 117, 095501 (2016)