Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 27: Organic/bio Molecules on Metal Surfaces III

O 27.6: Talk

Tuesday, April 1, 2014, 11:45–12:00, TRE Phy

Interaction of a Kondo impurity with its molecular ligand — •Jörg Meyer, Anja Nickel, Robin Ohmann, Loka Mani, Cormac Toher, Dmitry Ryndyk, Francesca Moresco, and Gianaurelio Cuniberti — Institute for Materials Science and Max Bergmann Center of Biomaterials, Center for Advancing Electronics Dresden, TU Dresden, 01062 Dresden, Germany

We investigated a Co containing organic molecule on different metal surfaces by STM and STS. On Ag(100) the molecule showed a prominent asymmetric peak at the Fermi level. To verify the Kondo nature of this peak, temperature dependent STS was applied and the resulting spectra were fitted with the Fano formula. Afterwards, we measured a grid of spectra with submolecular resolution to determine the shape of the Kondo resonance in different spots of the molecule. Interestingly, the asymmetry/Fano parameter q strongly changed around the molecule in a clearly non-radialsymmetric fashion, representing the influence of the molecular ligand on the resonances appearance. This is interpreted as signal transduction of the Kondo resonance via the molecular orbitals. Simulations to support this hypothesis are still ongoing. The strong influence of the local environment is further illustrated by the disappearance of the Kondo resonance on Cu(110). Instead of the asymmetric peak at the Fermi level we found a symmetric peak at -0.2 V. A dI/dV map of these states show the same spatial distribution like the Kondo resonance at the Fermi Level obtained from the specgrid measurements.