Regensburg 2013 – scientific programme
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O: Fachverband Oberflächenphysik
O 89: Surface Dynamics II
O 89.1: Talk
Friday, March 15, 2013, 10:30–10:45, H33
Spin polarized photoemission of gold surfaces coated with bacteriorhodopsin — •Matthias Kettner1, Benjamin Göhler1, Tal Z. Markus2, Volker Hamelbeck1, Georg F. Hanne1, Ron Naaman2, and Helmut Zacharias1 — 1Physikalisches Institut, Universität Münster, Germany — 2Department of Chemical Physics, Weizmann Institute, Rehovot, Israel
Electron spin polarization has been measured for photoelectrons emitted from a gold substrate and transmitted through physisorbed layers of the chiral membrane protein bacteriorhodopsin. Samples are irradiated by circularly as well as linearly polarized 213 nm laser radiation, exciting photoelectrons within the gold substrate which are transmitted through the proteins. Photoelectrons are analyzed by a time-of-flight detector yielding an "unstructured" spectrum up to 1.5 eV; an electron dichroism of up to 1.4 % is measured independent on the kinetic energy. Furthermore, a Mott polarimeter is used for spin analysis. In the present experiment electron spin polarization values of up to 15 % are obtained independent of the polarization of the incident light, similar to earlier work on ordered layers of double-stranded oligo-DNA [1]. The measured electron spin polarization shows a dependence on the preparation of the samples.
[1] B. Göhler, et al., Science 331, 894 (2011)