Dresden 2011 – scientific programme
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O: Fachverband Oberflächenphysik
O 51: Graphene III
O 51.5: Talk
Wednesday, March 16, 2011, 16:00–16:15, WIL B321
Illuminating the dark corridor in graphene: polarization dependence of angular resolved photoemission spectroscopy on graphene — •Isabella Gierz1, Jürgen Henk2, Hartmut Höchst3, Christian R. Ast1, and Klaus Kern1,4 — 1Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart, Germany — 2Max-Planck-Institut für Mikrostrukturphysik, 06120 Halle (Saale), Germany — 3Synchrotron Radiation Center, University of Wisconsin-Madison, Stoughton, WI 53589, USA — 4IPMC, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
We have used s- and p-polarized synchrotron radiation to image the electronic structure of epitaxial graphene near the K-point of the 2D Brillouin zone by angular resolved photoemission spectroscopy (ARPES). Part of the experimental Fermi surface is suppressed due to the interference of photoelectrons emitted from the two equivalent carbon atoms per unit cell of graphene’s honeycomb lattice [1]. We will show that by rotating the polarization vector, we are able to illuminate this ‘dark corridor’ indicating that the present theoretical understanding is oversimplified. Our measurements are supported by first-principles photoemission calculations, which reveal that the observed effect persists in the low photon energy regime.
[1] E. L. Shirley, L. J. Terminello, A. Santoni, and F. J. Himpsel, Phys. Rev. B 51, 13614 (1995)