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O: Fachverband Oberflächenphysik
O 55: Time-resolved spectroscopies II
O 55.5: Vortrag
Donnerstag, 26. März 2009, 16:00–16:15, SCH A315
Unoccupied band-structure and hot electron lifetimes in Pb quantum-wells — •Andreas Ruffing1, Stefan Mathias1, Frederik Deicke1, Martin Wiesenmayer2, Michael Bauer2, and Martin Aeschlimann1 — 1Department of Physics and Research Center OPTIMAS, University of Kaiserslautern, 67633 Kaiserslautern — 2Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24908 Kiel, Germany
Metallic quantum wells (QW) have been studied extensively in the recent past motivated by their potential to tune condensed matter properties via control of the quantum mechanical boundary conditions in these low-dimensional systems. Additional to the tuneability, these systems show interesting features in the electronic structure, such as avoided crossings, band gaps or modifications due to interaction with the substrate. All these features dominantly influence the decay dynamics of excited carriers. Our goal is to gain further knowledge in femtosecond hot electron dynamics by investigating these electronic features with time-resolved two-photon photoemission (2PPE) and a two-dimensional analyzer for parallel energy (E) and momentum (k||) detection. A prominent example of these systems are thin Pb films, which we investigated on a Cu(111) substrate. We will show the unoccupied band structure and discuss the according electron dynamics by means of angular resolved hot electron lifetime maps τ(E,k||).