Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 111: Oxides and Insulators: Adsorption II
O 111.8: Talk
Friday, March 16, 2018, 12:15–12:30, MA 041
C60 adsorption on a two-dimensional oxide quasicrystal — •Eva Maria Zollner1, Stefan Förster1, and Wolf Widdra1,2 — 1Martin-Luther-Universität Halle-Wittenberg, Halle, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, Halle, Germany
The recent observation of a two-dimensional oxide quasicrystal (OQC) derived from ultrathin films of BaTiO3 on Pt(111) demonstrates that quasicrystalline structures can emerge in the heteroepitaxial growth of conventional periodic materials [1]. Due to the complexity of QCs, studies on the relation between aperiodic order and physical properties are challenging. Therefore, QC surfaces have been tested as templates for the growth of two-dimensional single element QCs formed by molecular adsorbates [2]. Here we report the first adsorption studies on the BaTiO3-derived OQC using C60 molecules. Different coverages of C60 have been deposited on the OQC at different temperatures and characterized by LEED and STM. At room temperature C60 molecules form hexagonal islands at the OQC surface with preferential adsorption at step edges, which indicates a weak interaction with the OQC substrate. At temperatures below 150 K the diffusion of individual C60 molecules is strongly suppressed and small C60 islands are formed upon adsorption. Besides local hexagonal C60 arrangements, we find local C60 structure with quadratic arrangement. The latter being combined into local triangle-square tilings.
[1] S. Förster et al., Nature 502, 215 (2013).
[2] J. A. Smerdon et al., Nano Lett. 14, 1184 (2014).