Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 35: Poster Session I (Metal, semiconductor and oxide substrates: structure and adsorbates; Graphene)
O 35.7: Poster
Dienstag, 12. März 2013, 18:15–21:45, Poster B1
Final-State Diffraction Effects In Angle-Resolved Photoemission At An Organic-Metal Interface — •Bocquet F. C.1,2, Giovanelli L.2, Amsalem P.3, Petaccia L.4, Topwal D.4, Gorovikov S.4, Abel M2, Koch N.3, Porte L.2, Goldoni A4, and Themlin J.-M.2 — 1Peter Grünberg Institut, Forschungszentrum Jülich, 52425 Jülich, Germany — 2Aix-Marseille Univ, IM2NP, 13397 Marseille, France — 3Institut fur Physik, Humboldt-Universitat zu Berlin, 12489 Berlin, Germany — 4Sincrotrone Trieste, 34149 Trieste, Italy
The growth of organic thin films on metallic substrates has become a field of growing interest for organic electronics as well as for fundamental surface science [1]. We show that angle-resolved photoemission performed using low-energy photons on an organic-metal interface allows to clearly distinguish genuine interface states from features of substrate photoelectrons diffracted by the molecular lattice [2]. As a model system, an ordered monolayer of Zn-phthalocyanine is used as a diffraction lattice to probe the electronic band structure of a Ag(110) substrate. Photoemission close to normal emission geometry reveals strongly dispersive features absent in the pristine substrate spectra. Density functional theory modelling helped identifying these as bulk sp direct transitions undergoing surface-umklapp processes. The present results establish the important role of final-state diffraction effects in photoemission experiments at organic-inorganic interfaces.
[1] Bartels, Nature Chemistry 2 87 (2010) [2] Bocquet et al. Phys. Rev. B 84 241407(R) (2011)