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O: Fachverband Oberflächenphysik

O 55: Poster Session III - MA 141/144 (Methods: Atomic and Electronic Structure; Particles and Clusters; Heterogeneous Catalysis; Semiconductor Substrates: Epitaxy and Growth+Adsorption+Clean Surfaces+Solid-Liquid Interfaces; Oxides and Insulators: Solid-Liquid Interfaces+Epitaxy and Growth; Phase Transitions; Metal Substrates: Adsorption of Inorganic Molecules+Epitaxy and Growth; Surface Chemical Reactions; Bimetallic Nanosystems: Tuning Physical and Chemical Properties; Oxides and insulators: Adsorption; Organic, polymeric, biomolecular films; etc.)

O 55.72: Poster

Mittwoch, 27. Februar 2008, 18:30–19:30, Poster F

Spin-dependent Electron Transmission through Organized Organic thin Films — •Benjamin Göhler¹, Arne Rosenfeldt¹, Volker Hamelbeck¹, Georg F. Hanne¹, Helmut Zacharias¹, and Ron Naaman² — ¹Physikalisches Institut, Universität Münster — ²Department of Chemical Physics, The Weizmann Institute, Rehovot, Israel

Electron dichroism has been reported for vapours of chiral molecules [1]. The interaction of longitudinally spin-polarized electrons with chiral molecules can be different for two enantiomers or stated the other way around for one enantiomer and electrons of opposite helicities. The attenuation of polarized electron beams shows a dependence upon the spin of the electrons.

Here photoelectrons are detected that are emitted from a gold surface covered by an organized organic thin film (OOTF). Photoelectrons excited from gold by circularly polarized light have a longitudinal spin polarization of up to 15% [2]. The photoelectron yield of gold covered with OOTF also varies with the circular polarization of the incident laser light [3]. When the photon energy applied (5.9 eV) is not sufficient to ionize the adsorbed molecules but emit electrons from the gold substrate, those results suggest that the electron transmission through the organic layer is spin dependent. To analyze this spin filter effect a new set-up is built with a small-size conventional electron polarimeter (Mini Mott) to determine the spin polarization of the transmitted electrons through the OOTF. [1] PRL 74, 4803, 1995. [2] PRL 47, 374, 1981. [3] Science 283, 814, 1999.