Berlin 2018 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 89: Oxide and Insulator Surfaces: Structure, Epitaxy and Growth I
O 89.7: Vortrag
Donnerstag, 15. März 2018, 12:00–12:15, MA 041
A structure analysis of the BaTiO3-derived oxide quasicrystal in physical and internal space — •Sebastian Schenk1, Stefan Förster1, René Hammer1, and Wolf Widdra1,2 — 1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
Recently the formation of BaTiO3-derived and SrTiO3-derived 2-dimensional oxide quasicrystals (OQC) with 12-fold symmetry have been discovered on Pt(111) substrates [1,2]. Both OQCs exhibit a Niizeki-Gähler tiling which is composed by quadratic, triangular, and rhombic elements of equal side length. This tiling can be derived mathematically from cutting a periodic hyperhexagonal structure in the four-dimensional space and project it onto two dimensions, the so-called physical space. Here, we present a detailed analysis of the tiling characteristics as derived from atomically-resolved STM images which represent the physical space dimension. Not only the tiling frequency, but also their orientational distribution is determined to unravel the impact of the underlying periodic substrate to the OQC tiling. Additional information is gained from lifting the atomic coordinates into the four-dimensional hyperspace for a subsequent study of the internal space projection.
[1] S. Förster et al., Nature 502, 215 (2013)
[2] S. Schenk et al., J. Phys.: Condens. Matter 29, 134002 (2017)