Regensburg 2022 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 66: Oxide Surfaces 2
O 66.7: Vortrag
Donnerstag, 8. September 2022, 12:15–12:30, S053
Barium decorated Ti2O3 monolayers: a case study for Pd(111) substrates — •Friederike Wührl, Sebastian Schenk, Oliver Krahn, Stefan Förster, and Wolf Widdra — Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany
Oxides at the two-dimensional limit show a high flexibility in their structural properties ranging from hexagonal honeycomb structures to dodecagonal oxide quasicrystals (OQC) [1]. Recent work based on STM, surface x-ray diffraction (SXRD) and DFT calculations confirmed a structure model for oxide quasicrystals that explains this extraordinary structure as an aperiodically ordered Ti2O3 network with rings of different sizes on the metal support Pt(111), in which the largest rings are decorated with Ba ions [2]. The Ba ions form a self-similar tiling, which can be described through triangles, squares and rhombuses. In this contribution we report on a sequence of long-range ordered structures observed in BaxTi2O3+y on Pd(111) that are closely related to the OQC. We present a series of structures ranging from a Ba0.66Ti2O3 to a BaTi2O3.5 stoichometry. By varying the Ba content, we observe a transition from a triangle-square tiling via triangle-square-rhombus tilings to one consisting of triangles and rhombuses only [3]. It will be discussed how the Ba density sets the ratio of four to seven to ten membered rings in the Ti2O3 backbone.
[1] S. Förster et al., Nature 502, 215 (2013).
[2] E. Cockayne et al., Phys. Rev. B 93, 020101(R) (2016).
[2] F. E. Wührl et al., Phys. Status Solidi B, 2100389 (2021).