Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 65: Graphene V
O 65.4: Vortrag
Donnerstag, 29. März 2012, 11:15–11:30, MA 041
Investigation of the electronic structure of bilayer graphene on Ni(111) — •Martin Weser1, Roland Koch2, Elena Voloshina3, Alex Generalov1,4, Hendrik Vita1, Thomas Seyller2, Karsten Horn1, and Yuriy S. Dedkov5 — 1Fritz-Haber Institut, Berlin, Germany — 2Universität Erlangen-Nürnberg, Erlangen, Germany — 3Freie Universität, Berlin, Germany — 4Technische Universität Dresden, Germany — 5SPECS Surface Nano Analysis GmbH, Germany
Among the many proposed applications of graphene in electronic devices, its use as a spin-filter has received attention, because the electronic structure of graphene and that of close-packed surfaces of ferromagnetic metals such as Ni and Co overlap only for the minority spin bands at the Fermi level. The effect was predicted to strongly increase with increasing of the number of graphene layers. We have developed a method for multilayer preparation using pyridine cracking on Ni(111) in ultrahigh vacuum. We characterize our multilayer films using low energy electron diffraction, core and angle-resolved valence level photoelectron spectroscopy. Multilayers are found to grow in a manner where consecutive layers are rotated against each other by well-defined angles, a fact that may lead to a decoupling of layers as found in multilayer growth on the carbon face of SiC(000-1). It was found that twisted stacking occurs for the overlayer, with two favorable rotation angles. In spite of this arrangement, spin filtering may still be possible because of the specific shape of the majority spin states in Ni(111) at EF.