Dresden 2014 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 45: Poster IV: One-Dimensional Metals: Reality or Fiction
DS 45.27: Poster
Donnerstag, 3. April 2014, 16:00–19:00, P1
Time- and angle-resolved 2PPE studies of Pb nanowires on Si(557) — •Abdul Samad Syed1, Vesna Mikšić Trontl1, Manuel Ligges1, Mathias Sandhofer1, Ishita Agarwal1, Isabella Avigo1, Daniel Lückermann2, Christoph Tegenkamp2, Herbert Pfnür2, and Uwe Bovensiepen1 — 1Fakultät für Physik, Univ. Duisburg-Essen — 2Institut für Festkörperphysik, Leibnitz Univ. Hannover
Strongly anisotropic systems, like, e.g., metallic nanowire arrays grown on semiconducting surfaces, are expected to exhibit significantly different electronic dispersion - along and perpendicular to the wire structure. Angle-resolved photoemission is an excellent tool to study electronic band dispersion, but is often limited to (i) one momentum direction in a single measurement and (ii) the occupied electronic structure. Here, we report on femtosecond-laser based two-photon photoemission experiments on Pb/Si(557) nanowires that map the unoccupied electronic structure. Using a position-sensitive time-of flight spectrometer [1], the dispersion along and perpendicular to the wires can be analyzed simultaneously in a single measurement. Furthermore, by delaying two light pulses with respect to each other, the lifetimes of these unoccupied electronic states can be measured in a pump-probe experiment. We present first time- and momentum-resolved studies on the unoccupied states in this system. We gratefully acknowledge funding by the DFG through FOR1700.
[1] Kirchmann et al., Appl. Phys. A 91,211 (2008)