Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 17: Zeitaufgelöste Spektroskopie I

O 17.1: Vortrag

Dienstag, 25. März 2003, 11:15–11:30, FOE/ORG

Image-potential states on stepped Cu(001)-surfaces — •Manfred Roth, Martin Pickel, Jinxiong Wang, Martin Weinelt, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7/A3, 91058 Erlangen

Steps are defects common to any real surface. Cu(11l) surfaces exhibit (001)-like terraces and straight step edges of monoatomic height running along the [110]-direction [1,2]. The density and regularity of the steps vary along the series of Cu(11l) surfaces. The dynamics of image-potential states on these Cu(11l) surfaces has been studied for l = 5 to 15 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 [3]. A direction-dependent resonant scattering process with large momentum transfer was observed [4], which leads to strong interband scattering from the n=2 to the n=1 image-potential state band and an asymmetric behavior of the lifetime in the n=1 image-potential state band. This scattering mainly occurs in the "upstairs direction" of the stepped surfaces. The influence of the step density and regularity on decay, dephasing and resonant scattering will be discussed.

[1] M. Giesen, Surf. Sci. 370, 55 (1997)

[2] N. Reinecke and E. Taglauer, Surf. Sci. 454-456, 94 (2000)

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

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