title: Electronic structure at the perylene-tetracarboxylic acid dianhydride/Ag(111) interface studied with two-photon photoelectron spectroscopy.
abstract: The electronic structure of the prototype metal/organic contact 3,4,9,10-perylene-tetracarboxylic acid dianhydride (PTCDA) on a Ag(111)-surface has been investigated using time- and angle-resolved two-photon photoelectron spectroscopy (2PPE). Our analysis addresses particularly the nature of the interface state (IS) emerging at the interface due to the substrate-adsorbate interaction [C. H. Schwalb, S. Sachs, M. Marks et al., Phys. Rev. Lett. 101, 146801 (2008)]. Its free-electron-like dispersion and a possible backfolding at the surface Brillouin zone boundaries are discussed. Time-resolved pump-probe experiments reveal the inelastic electron lifetime along the dispersion parabola and show its decrease for increasing parallel momentum. The temperature dependence of the peak linewidth indicates a coupling of the IS to molecular vibrations. Moreover, additional aspects are addressed, such as the determination of the electron attenuation length of photoelectrons for low kinetic energy originating from the IS and the work function change of the sample upon PTCDA adsorption with very high energy resolution.
authors.affiliation: Universität Würzburg, Experimentelle Physik II, Am Hubland, Germany.
authors.forename: Sönke
authors.initials: S
authors.lastname: Sachs
authors.forename: Christian H
authors.initials: CH
authors.lastname: Schwalb
authors.forename: Manuel
authors.initials: M
authors.lastname: Marks
authors.forename: Achim
authors.initials: A
authors.lastname: Schöll
authors.forename: Friedrich
authors.initials: F
authors.lastname: Reinert
authors.forename: Eberhard
authors.initials: E
authors.lastname: Umbach
authors.forename: Ulrich
authors.initials: U
authors.lastname: Höfer