Regensburg 2013 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 29: Organic/bio Molecules on Metal Surfaces III

O 29.9: Vortrag

Dienstag, 12. März 2013, 12:30–12:45, H38

Adsorption of V-TCNE on Ag(001): results from ab-initio calculations — •Thorsten Deilmann, Peter Krüger und Michael Rohlfing — Institut für Festkörpertheorie, Universität Münster, D-48149 Münster, Germany

Organic molecules coupled to transition metal atoms offer interesting physical properties like large magnetic moments. Recently, Wegner et al. [1] have shown that tetracyanoethylen (TCNE) and vanadium on Ag(001) can be induced by STM manipulation to form a strong chemical bond. Here, we present a theoretical study on the adsorption of V-TCNE on Ag(001). Optimized structures, adsorption energies, electronic and magnetic properties have been calculated employing density-functional theory. TCNE adsorbs in on top position with the nitrogen atoms bound to Ag surface atoms. Due to the interaction with the surface, an electron transfer occurs and the molecule is negatively charged. The calculated density of states, as well as the simulated STS and STM images show good agreement with respective experimental data [1].

Addition of vanadium leads to a spin-polarized system. We find that V atoms adsorb only at the hollow position on Ag(001). In the energetically most favored structure of V-TCNE, two nitrogen atoms are bound to a vanadium atom. Close to the Fermi level, the local density of states shows a dominant V induced peak that is distinctly broadened due to the molecule-substrate interaction.

[1] D. Wegner et al., Phys. Rev. Lett. 103, 087205 (2009)