Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Metal substrates 1

O 29.7: Vortrag

Dienstag, 6. September 2022, 12:00–12:15, S052

The role of Adatoms for the Adsorption of F4TCNQ on Au(111) — •Richard Berger, Andreas Jeindl, Lukas Hörmann, and Oliver Hofmann — TU Graz Institut für Festkörperphysik, Graz, Österreich

Molecular adsorption on inorganic substrates often includes the incorporation of native adatoms within the adsorbate layer. The presence of the adatom in the adlayer causes significant changes in the electronic structure of the interface affecting properties such as the adsorption geometry, the bonding type, and the work function. Here we investigate the adsorption of F4TCNQ on Au (111), which is a prototypical system for the adsorption of an acceptor type molecule on a metallic substrate. Using density functional theory, we show that incorporating adatoms significantly changes the interface charge transfer and modifies the Fermi-level pinning mechanism for the adsorbed species. Furthermore, we find that the 5d orbitals of the Au adatom hybridize with the F4TCNQ molecular orbitals, introducing covalent coupling within the adlayer. The combination of this effect explains why the incorporation of adatoms, despite the high cost of extracting them from the bulk, is energetically favorable.