Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 85: Electron and spin dynamics I
O 85.7: Vortrag
Donnerstag, 17. März 2011, 18:00–18:15, WIL A317
Electron Spin Dependent Transmission through Self-assembled Monolayers of dsDNA — •Matthias Kettner1, Benjamin Göhler1, Daniel Nürenberg1, Volker Hamelbeck1, Tal Markus2, Zeev Vager3, Georg F. Hanne1, Ron Naaman2, and Helmut Zacharias1 — 1Physikalisches Institut, Westfälische Wilhelms-Universität, Münster, Germany — 2Department of Chemical Physics, Weizmann Institute, Rehovot, Israel — 3Department of Particle Physics, Weizmann Institute, Rehovot, Israel
Electron spin polarization has been measured for photoelectrons emitted from a gold substrate and transmitted through a self-assembled monolayers of chiral double-stranded DNA molecules. Electron spin polarization values of up to 60% are obtained independent of the polarization of the incident light. The measured electron spin polarization shows a dependence on the thickness of the layer, tested by varying the length of the oligomers. For surfaces covered with single-stranded DNA molecules, which do not form a well ordered layer, no significant spin polarization could be observed.
Samples are irradiated by either circularly or linearly polarized 213nm laser radiation, exciting photoelectrons within the gold substrate, not being sufficient to ionize adsorbed dsDNA molecules. Photoelectrons are analysed either by a time-of-flight detector or a small size conventional Mott polarimeter for spin analysis.