Berlin 2018 – wissenschaftliches Programm
O 5.9: Vortrag
Montag, 12. März 2018, 12:45–13:00, MA 042
Metal-Phthalocyanines on Noble Metal Surfaces: A Systematic Investigation With Respect to Strong Correlation Effects — •Manuel Grimm, Dennis Hein, Christian Metzger, Martin Graus, Achim Schöll, and Friedrich Reinert — Exp. Physik 7, Universität Würzburg, 97074 Würzburg, Germany
Metal-organic interfaces provide an ideal playground to study fundamental interaction mechanisms. In particular cases, these can lead to electronic correlations which cannot be described within a single particle picture. In case of some adsorbate/substrate combinations the LUMO of molecules in the first layer is partially occupied due to charge transfer from the metal substrate. As a result such samples, e.g. NTCDA or CuPc on Ag(111) [1,2] show a sharp Kondo resonance at the Fermi energy in high resolution photoelectron spectroscopy (PES) experiments. Here we present a systematic study of these resonance features. We analyze the influence of sample temperature and vary the bonding strength and charge transfer at the interface by changing the adsorbate and the orientation of the substrate surface. While we observe a Kondo scenario for NiPc and CuPc on Ag(111) which is explained within a Single Impurity Anderson model (SIAM), a more complicated behavior occurs on Ag(100) and Ag(110) surfaces. In the latter cases the NiPc and CuPc LUMO is still partially filled at room temperature, but starts to shift to larger binding energies upon cooling. This also leads to a shift of the sharp resonance peak away from the Fermi energy, which demands for an explanation beyond the SIAM.
 Schoell Science 329, 303 (2010)  Ziroff PRB B85 (2012)