Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 24: Electronic Structure: Surface Magnetism and Spin Phenomena

MA 24.8: Poster

Dienstag, 8. März 2016, 18:15–20:30, Poster E

Inelastic spin excitations and many-body effects in Fe porphins — •Laëtitia Farinacci, Nino Hatter, Sonja Schubert, Benjamin W. Heinrich, and Katharina J. Franke — Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Magnetism of 3d metals in molecules is commonly treated by crystal field theory. Nonetheless, in case of strong hybridization of the d levels with ligand orbitals this approach may be insufficient. Modification of the conjugated π system could give insight in the influence of such hybridization effects.

Using STM and STS we investigate the properties of the H2P porphins adsorbed on Au(111). After deposition, only monomers are observed on the surface. Annealing to 630 K triggers their polymerization and metalation of the molecules is achieved by Fe deposition at 300 K.

In spectroscopy, FeP monomers and dimers present various features around the Fermi energy above their Fe centers as well as above specific parts of their molecular ligand. Depending on the nature and adsorption site of the molecules, steps localized at energies up to ± 14 mV as well as a zero bias anomaly similar to a Fano-line shape can be observed. These features result from an interplay between inelastic spin excitations and many-body effects: their shape, broadening and localization cannot be fully addressed by crystal field theory and have to be related to the mixing of the Fe d levels with organic orbitals reported by theory [1] as well as to various couplings to the substrate.

[1] M.E. Ali, et al., J. Phys. Chem. B 116, 5849 (2012).