Dresden 2014 – scientific programme
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O: Fachverband Oberflächenphysik
O 80: Surface Dynamics I
O 80.2: Talk
Thursday, April 3, 2014, 16:15–16:30, GER 38
Spin-resolved electron transmission through chiral molecules and proteins on metal surfaces — •Matthias Kettner1, Benjamin Göhler1, Debabrata Mishra2, Tal Z. Markus2, 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 aluminum and gold substrates and transmitted through adsorbed layers of the chiral membrane protein bacteriorhodopsin and the amino acid alanine. The samples are irradiated by 213nm laser radiation exciting photoelectrons within the metal substrate. These photoelectrons are then transmitted through the chiral layer and analyzed by a Mott polarimeter. The case of bacteriorhodopsin which is physisorbed on an aluminum substrate, electron spin polarization values of up to +15% are obtained independent of the polarization of the incident light. Taking earlier studies of bacteriorhodopsin on a gold substrate into account, spin-orbit-coupling of the substrate seems to have a minor influence [1]. Moreover the electron spin polarization shows a dependence on the coverage of the substrate. These studies are extended to the chiral amino acid polyalanine which is self-assembled on a gold surface. The results indicate that also in this case the interaction of chiral layers with the electrons depends on the spin orientation. This effect may enable the design of efficient spin filters for spintronic applications.
[1] D. Mishra, et al., PNAS 110, 14872 (2013)