Regensburg 2004 – scientific programme

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O: Oberflächenphysik

O 37: Zeitaufgelöste Spektroskopie I

O 37.4: Talk

Thursday, March 11, 2004, 16:30–16:45, H36

Image-potential states on stepped Cu(11l) surfaces — •Manfred Roth, Martin Weinelt, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7/A3, 91058 Erlangen

The dynamics of image-potential states on stepped Cu(11l) surfaces has been studied with time- and angle-resolved two-photon photoemission. In comparison to the Cu(001) surface the image-potential states on the stepped surfaces show increased decay and dephasing rates [1]. A direction-dependent resonant scattering process with large momentum transfer was observed [2], which leads to strong interband scattering from the n=2 to the n=1 image-potential state band. The intensity of this scattering depends on the regularity and the mean terrace width of the step arrangement [3]. Further the anisotropic scattering leads to an asymmetric behavior of the lifetime in the n=1 image-potential-state band. This can be explained by a direction-dependent reflection at the step edges, found by scanning tunneling spectroscopy [4]. The dependence of the mentioned effects on the step density will be discussed.

[1] M. Roth, M. Pickel, J. Wang, M. Weinelt, and Th. Fauster, Appl. Phys. B 74, 661 (2002)

[2] M. Roth, M. Pickel, J. Wang, M. Weinelt, and Th. Fauster, Phys. Rev. Lett. 88, 096802 (2002)

[3] M. Roth, M. Pickel, M. Weinelt, and Th. Fauster, Appl. Phys. A 78, 149 (2004)

[4] M. Roth, M. Weinelt, Th. Fauster, P. Wahl, M. A. Schneider, L. Diekhöner, and K. Kern, Appl. Phys. A 78, 155 (2004)