Dresden 2017 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 47: Electronic Structure of Surfaces: Magnetism and Spin Phenomena
O 47.3: Poster
Dienstag, 21. März 2017, 18:30–20:30, P1A
Enantiomer-dependency of spin orientation in photoelectron transmission through heptahelicene — •Matthias Kettner1, Daniel Nürenberg1, Johannes Seibel2, Karl-Heinz Ernst2, and Helmut Zacharias1 — 1Physics Institute und Center for Soft Nanoscience, University of Münster, Germany — 2Nanoscale Materials Science, EMPA, Switzerland
Spin transport electronics (spintronics) enables a new generation of efficient electronic and non-volatile memory devices. Though the concept of spintronics is well known, the field still lacks devices that work under ambient conditions. Experiments on self-assembled monolayers of double stranded DNA [1,2] and oligopeptides [3] indicated a very efficient spin filtering behavior of the molecules at room temperature.
In present experiments enantiopure M- and P-heptahelicene molecules are evaporated onto noble metal single crystal surfaces. The molecules arrange themselves to a highly ordered monolayer [4]. Samples are then irradiated with λ = 213 nm laser radiation to generate photoelectrons from the substrate. These electrons are transmitted through the heptahelicene layer and analyzed with regard to their average longitudinal spin orientation by a Mott polarimeter. The sign of the spin polarization is related to the helicity of the enantiomer whereas an influence of substrate on the spin-filter effect has not been observed.
[1] Göhler, B. et al., Science 2011, 331, 894. [2] Kettner, M. et al., Adv. Mater. Interfaces, 2016, 3, 1600595. [3] Kettner, M. et al., J. Phys. Chem. C 2014, 119, 26. [4] Ernst, K.-H., Acc. Chem. Res. 2016, 49, 1182.