Seminar Festkörper- und Grenzflächenphysik KOMET - experimentell

 May 7, 2013 at noon c.t. in Newton-Raum, Staudingerweg 9, 1. Stock, Raum 122 (Nebengebäude)

Prof. Dr. Hans-Joachim Elmers
Institut für Physik, KOMET 5
elmers@uni-mainz.de

Prof. Dr. H. J. Elmers

Note: Ansprechpartner: Herr Schönhense

Spin and Momentum Dependent Lifetimes of Image-Potential States
Dr. Marko Wietstruk (Freie Universität Berlin, Inst. f. Experimentalphysik (Gruppe Weinelt))


Two-photon photoemission (2PPE) is a valuable tool in order to investigate unoccupied image-potential states (IPS). Using a cylindrical sector analyzer (CSA) in combination with a spin polarizing LEED detector lifetimes of IPS in Nickel have been measured. The n=1 IPS shows a small difference in the lifetimes of majority and minority states, which becomes even larger for the n=2 IPS.
Furthermore lifetimes of IPS on Cu(1 1 11) have been measured. Here we found differences in lifetimes depending on the electron momentum relative to the surface structure. A simultaneous measurement at different k|| values was essential. This could be achieved by using the wide-angle mode of the time-of-flight spectrometer Themis.