Berlin 2015 – wissenschaftliches Programm
O 28.6: Vortrag
Dienstag, 17. März 2015, 15:15–15:30, MA 041
Observation of Natural X-Ray Birefringence of Graphene — •Christine Jansing1, Marc F. Tesch1,2, Markus Gilbert1, Andreas Gaupp1, Hans-Christoph Mertins1, Andrey Sokolov2, Dong Hee Shin3, Suk-Ho Choi3, Heiko Timmers4, Dominik Legut5, and Peter M. Oppeneer6 — 1Münster University of Applied Sciences, Stegerwaldstr. 39, D-48565 Steinfurt — 2HZB, Albert Einstein Str. 15, D-12489 Berlin — 3Research School of Physics and Engineering, Department of Electronic Materials Engineering, Australian National University, Canberra, ACT 0200, Australia — 4School of Physical, Environmental and Mathematical Sciences, University of New South Wales Canberra, PO Box 7916, Canberra BC 2610, Australia — 5Nanotechnology Centre, Ostrava, Czech Republic — 6Depart. of Physics, Uppsala Uni., Box 530, S-751 21 Uppsala, Sweden
We present the first experimental results that demonstrate the x-ray natural birefringence and the natural linear dichroism (XNLD) of graphene and compare these to our ab-initio calculations. The effects have been detected at the C 1s edge of a graphene monolayer on Cu using polarization spectroscopy in reflection with linearly polarized radiation at the UE56-2-PGM2 beamline at BESSY II. Upon reflection the polarization plane rotates showing an unusually large rotation value of 33° at the π*-states near 285 eV. Additionally the polarization of the light changes from linear to circular with a maximum value of Pcirc = 0.95. The new results for a monolayer graphene are compared with those obtained for highly-ordered pyrolitic graphite (HOPG).