Regensburg 2022 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 55: Poster Wednesday: Organic Molecules at Surfaces 2

O 55.4: Poster

Mittwoch, 7. September 2022, 18:00–20:00, P4

Changes in the coupling of a single-molecule magnetic moment to a Cooper pair condensate by the sequential removal of molecular moieties — •Stefan Schulte¹, Nicolas Néel¹, Krisztian Palotas², and Jörg Kröger¹ — ¹Institut für Physik, Technische Universität Ilmenau, Ilmenau, Germany — ²Institute for Solid State Physics and Optics, Wigner Research Center for Physics, Budapest, Hungary

Using the tip of a STM chemical reactions are induced in organic 5,10,15,20-tetrakis(4-bromophenyl)-porphyrin-cobalt molecules adsorbed on superconducting Pb(111). Two chemical reactions, the dehalogenation and dephenylation of the molecules are presented. Yu-Shiba-Rusinov bound states occur in the superconductor energy gap only after the entire dephenylation of the molecule. The presence of the intragap resonances is related to an unoccupied molecular orbital that is confined to the atomic magnetic center (Co) of the porphyrin. From the energy position and spectral weight of these intragap resonances, a weak interaction between the molecular magnetic moment and the Cooper pair condensate is inferred. The electron-hole asymmetry of the bound states exhibits a spatial oscillation with a wavelength that evidences the exchange coupling of the molecular magnetic moment to the sp-sheet of the Fermi surface. The very low binding energy of the Yu-Shiba-Rusinov levels is consistent with the observed absence of the Kondo effect. Funding by the DFG through KR 2912/10-1 and KR 2912/10-3 is acknowledged.