Dresden 2014 – wissenschaftliches Programm

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SYOM: Symposium One-dimensional Metals: Reality or Fiction

SYOM 2: Posters: One-Dimensional Metals: Reality or Fiction (jointly organized by DS, HL, O, TT)

SYOM 2.27: 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)