Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 34: Poster Session I (Graphene; Plasmonics and nanooptics; Coherence and coherent control in nanophotonics and plasmonics)

O 34.47: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster E

Plasmons in Pb nanowire arrays : Between one and two dimensions — •Tammo Block, Christoph Tegenkamp, Jens Baringhaus, Karthiga Kanthasamy, and Herbert Pfnür — Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstrasse 2, 30167 Hannover, Germany

Electron energy loss spectroscopy with both high energy and momentum resolution (ELS-LEED) was used to investigate the plasmon dispersion of arrays of Pb nanowires in the monolayer regime on a vicinal Si(557) substrate. While for coverages close to the physical monolayer (at 1.3ML) a true one-dimensional (1D) plasmon loss can be found, a wavelength-dependent transition from 1D to 2D properties takes place in the range from 1.2 to 1.4 monolayers. Due due to the high anisotropy in the system at all coveragess, the dispersion curves exhibit 1D characteristics in both directions, perpendicular and along the Pb wire direction. The Pb-induced refacetting of the Si(557) surface, which depends on Pb coverage seems to be the reason for this behavior, because both effective system sizes and coupling strength between miniterraces changes while increasing the Pb coverage.