Regensburg 2019 – scientific programme
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O: Fachverband Oberflächenphysik
O 49: Metal Substrates III: Structure, Epitaxy and Growth
O 49.1: Talk
Wednesday, April 3, 2019, 10:30–10:45, H5
Internal space analysis of a dodecagonal oxide quasicrystal and its approximants — •Sebastian Schenk1, Stefan Förster1, and Wolf Widdra1,2 — 1Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle, Germany
Two-dimensional oxide quasicrystals (OQC) with 12-fold symmetry have recently been derived from ultrathin perovskites on Pt(111) substrates [1,2]. They exhibit a tiling generated from quadratic, triangular, and rhombic elements of equal side length. By lifting the atomic coordinates of the tiling to a four-dimensional hyperspace, the structural properties of these monolayer structures are fully captured. The projection of the four-dimensional coordinates onto the so-called internal space allows a detailed analysis of the long-range ordering of the quasicrystal and a more precise differentiation between quasicrystals and their periodic approximant structures. Two different measures for the strength of the approximant structures will be given. As a tool for distinguishing defective quasicrystals from complex large unit cell periodic structures, the point distribution in the internal space and the phason strain matrix are discussed.
[1] S. Förster et. al., Nature 502, 215 (2013)
[2] S. Schenk et. al., J. Phys.: Condens. Matter 29, 134002 (2017)