Regensburg 2004 – wissenschaftliches Programm

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O: Oberflächenphysik

O 45: Zeitaufgelöste Spektroskopie II

O 45.7: Vortrag

Freitag, 12. März 2004, 12:45–13:00, H39

Scattering by Cu adatoms between image-potential bands on Cu(001) — •Klaus Boger, Martin Weinelt, and Thomas Fauster — Lehrstuhl für Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7, 91058 Erlangen

With increasing resolution and sensitivity of photoelectron spectroscopy the influence of defects is becoming more and more obvious. The scattering processes induced by adsorbate atoms can be studied by time- and angle-resolved two-photon photoemission. We have examined the dynamics of electrons in image-potential states on the Cu(001) surface for different coverages of statistically distributed Cu adatoms. The following scattering mechanisms were distinguished [1]: Scattering into the bulk, elastic and inelastic intraband scattering, resonant and inelastic interband scattering. The rates for these different processes were estimated by modeling the time-resolved measurements with optical Bloch equations. By varying the defect density the source of the various processes can be identified: The Cu adatoms mainly provoke elastic scattering. Inelastic scattering is due to interaction with electrons in the bulk.

[1] K. Boger, M. Weinelt, J. Wang, Th. Fauster, Appl. Phys. A 78, 161 (2004)