SKM 2023 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 47: 2D Materials II: Growth, Structure and Substrate Interaction I

O 47.10: Vortrag

Mittwoch, 29. März 2023, 12:45–13:00, GER 37

The transformation of 2D honeycombs into dodecagonal quasicrystals — •Stefan Förster, Loi Vinh Tran, Martin Haller, Sebastian Schenk, and Wolf Widdra — Institute of Physics, Martin-Luther-Universität Halle-Wittenberg, 06120 Halle, Germany

Oxide quasicrystals are 2D materials with an aperiodic dodecagonal symmetry [1]. Starting from a binary oxide Ti₂O₃ honeycomb structure on Pt(111), the Ti_nO_n ring structure with n=6 is transformed into a network of rings with ring sizes of n= 4, 5, 7 and 10 in the presence of Ba atoms. In these networks, n=7 rings host one Ba atom and n=10 rings host two [23].

In this contribution, the basic mechanisms for the network transformation are discussed. Stone-Wales transformations are the key mechanism to realize n=4...7 rings. In addition, by incorporating an additional oxygen atom, two neighboring n=6 rings convert into a n=10 ring [3]. The amount of Ba controls this conversion process and leads to a sequence of long-range ordered structures including a well-defined quasicrystal.

[1] S. Förster, K. Meinel, R. Hammer, M. Trautmann, and W. Widdra, Nature 502, 215 (2013)

[2] E. Cockayne et. al, Phys. Rev. B 93, 020101(R) (2016)

[3] S. Schenk, O. Krahn, E. Cockayne, H. L. Meyerheim, M. DeBoissieu, S. Förster, and W. Widdra, Nat. Commun, accepted (2022)