Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 41: Graphene III
O 41.9: Vortrag
Mittwoch, 28. März 2012, 12:30–12:45, MA 041
Electronic spectrum and structure of an epitaxial graphene superlattice on SiC — •Konstantin Emtsev1, Stiven Forti1, Camilla Coletti2, and Ulrich Starke1 — 1Max Planck Institute for Solid State Research, Stuttgart, Germany — 2Center for Nanotechnology Innovation @ NEST, Istituto Italiano di Tecnologia, Pisa, Italy
The electronic spectrum of graphene can be altered profoundly by the presence of an external potential that is periodic on an atomic scale [1]. Experimentally, such perturbations are sought after in graphene grown epitaxially on a crystalline substrate with commensurate or incommensurate lattice arrangements. In the present work we address the electronic and structural properties of such a graphene superlattice realized on a SiC substrate. We utilize the atomic intercalation phenomenon established earlier [2, 3] in order to create a new heterointerface graphene/copper/SiC. The samples were characterized by high resolution ARPES, XPS and LEED. As observed by LEED, the modified interface imposes a new long range reconstruction on graphene as opposed to as-grown epitaxial graphene on SiC. Changes in the electronic valence band spectrum of the graphene film detected by ARPES are related to a structural transformation of the graphene layer that we derive from XPS core level spectra. We compare our data to other epitaxial graphene systems and theoretical predictions.
[1] C.H. Park et al., Nat. Physics, 4, 213 (2008) [2] I. Gierz et al., Phys. Rev. B, 81, 235408 (2010) [3] K.Emtsev et al., Phys. Rev. B, 84, 125423 (2011)