Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 14: Organic-inorganic hybrid systems and organic films II
O 14.3: Talk
Monday, March 12, 2018, 15:45–16:00, MA 042
Oligomers on nanostructured surfaces: Adsorption-induced alteration of the surface reconstruction — •Laura Katharina Scarbath-Evers1, Milica Todorović2, René Hammer1, Wolf Widdra1, Daniel Sebastiani1, and Patrick Rinke2 — 1Faculty of Natural Sciences II, Martin-Luther University, Halle-Wittenberg — 2Department of Applied Physics, Aalto University, Finland
Theoretical studies of organic adsorbates on metal surfaces have mainly focused on the adsorption of small molecules on ideal surfaces. However, many surfaces, e.g. low index surfaces of Au, Ir, and Pt, have complex reconstructions that are challenging for surface science studies. In this work, we approach such complex (or nano-structured) surfaces with a combination of density-functional theory (DFT) calculations and scanning tunnelling microscopy (STM) measurements for the example of the α-sexithiophene (α-6T) oligomer adsorbed on the reconstructed Au(100) surface. We find that due to its corrugation pattern the reconstructed Au(100) surface offers a wide range of adsorption sites than can be broadly classified into on-ridge and in-valley types with energetic adsorption preferences for the latter. Surprisingly, adsorption in energetically ill-favored on-ridge positions leads to strong alterations of the surface reconstruction, facilitated by the “soft” nature of gold. As a result of electrostatic effects and charge transfer between the surface and the molecule, α-sexithiophene displaces the ridge instead of migrating into the valley.