Dresden 2009 – scientific programme

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O: Fachverband Oberflächenphysik

O 53: Nanostructures at surfaces: Dots, particles, clusters III

O 53.14: Talk

Thursday, March 26, 2009, 18:15–18:30, SCH A215

Pt dimers landing on Cu(001): an ab initio approach — •George Pal, Georg Lefkidis, and Wolfgang Hübner — Fachbereich Physik, Technische Universität Kaiserslautern, P.O.Box 3049, 67653 Kaiserslautern, Germany

We present real-space first-principles calculations for the adsorption of not only one but also two Pt clusters on a non-magnetic Cu(001) substrate. Considering that the interaction of adsorbates on surfaces is a local phenomenon, a representation of the substrate by a large cluster of 74 Cu atoms allows one to treat the electronic structures of both systems, i.e., the adsorbate and the surface, on equal footing. Using highly correlated quantum chemistry, we investigate different scenarios of soft-landing of Pt dimers on the substrate, for which we also optimize the Pt-Pt distance, and we compute the electronic excited states, which yields the optical absorption spectrum, on top of the electronic configuration at equilibrium geometry.

By analyzing the absorption spectra and the electronic densities of states we are able not only to characterize the interactions between the adsorbates and the substrate, but also to identify the surface-mediated interactions among the dimers. The latter is very important for technological applications since in experimental setups metallic substrates can alter the properties of the adsorbates, thus leading to new physics.

[1] Y. Pavlyukh, J. Berakdar and W. Hübner, Phys. Rev. Lett. 100, 116103 (2008)

[2] G. Pal, G. Lefkidis and W. Hübner, submitted to J. Phys. Chem.