Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 28: Organic Molecules at Surfaces 3: Theory

O 28.8: Vortrag

Dienstag, 6. September 2022, 12:15–12:30, S051

Interlayer orbital overlap governing thin-film geometry: the role of interfacial charge transfer — •Fabio Calcinelli, Andreas Jeindl, Lukas Hörmann, and Oliver Hofmann — Institute of Solid State Physics, NAWI Graz, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria

Organic thin films exhibit a large structural variability, and the substrate on which they grow has a relevant influence on their polymorphism. Predicting which structure a thin film will assume on a substrate is impossible through traditional first-principle modeling alone, because of the combinatorial explosion in the number of possible polymorphs. However, recent developments in machine-learning assisted structure search have made structure-to-property investigations accessible. Employing smart-data machine learning, we demonstrate the impact that different substrates can have on the geometry of the first two layers of a thin film. We identify the energetically most favourable geometries for benzoquinone on silver and on graphene, and compare their electronic properties. While the polymorphs formed in the first layer of benzoquinone are very similar, for the second layer we find two significantly different structures. We explain this difference as an effect of the interplay between different charge transfer on the two substrates, and different interlayer orbital overlap for the two structures. Furthermore, we investigate the systematic impact of interlayer orbital overlap in defining the most stable polymorphs for different charge transfers.