Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 29: Zeitaufgelöste Spektroskopie II

O 29.4: Vortrag

Donnerstag, 27. März 2003, 12:00–12:15, FOE/ORG

Interband scattering between image-potential states on clean and adsorbate-covered Cu(001) surfaces — •Klaus Boger, Jinxiong Wang, Martin Weinelt, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7/A3, 91058 Erlangen

We have examined the dynamics of electrons in image-potential states on the Cu(001) surface by means of time- and angle-resolved two-photon photoemission for different coverages with statistically distributed Cu adatoms. Scattering of electrons from the second (n=2) to the bottom of the first (n=1) image-potential band is observed with a contribution of about 10% to the total scattering rate independent of the Cu coverage. We attribute this to inelastic scattering with electrons in the substrate. At energies above the bottom of the n=2 band resonant scattering from the n=2 to the n=1 image-potential band is found. The rate for that process is low on the clean surface and increases with the concentration of Cu scatterers. At coverages of about 2% of a monolayer a saturation contribution of 35% to the total scattering rate is reached.