Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 4: Graphene I

O 4.2: Talk

Monday, March 26, 2012, 10:45–11:00, MA 041

Local Gating of an Ir(111) Surface Resonance by Graphene Islands — •Simon Johannes Altenburg¹, Jörg Kröger², Tim Wehling³, Burkhard Sachs³, Alexander Lichtenstein³, and Richard Berndt¹ — ¹Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, D-24098 Kiel, Germany — ²Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau, Germany — ³I. Institut für Theoretische Physik, Universität Hamburg, D-20355 Hamburg, Germany

The infuence of graphene islands on the electronic structure of the Ir(111) surface is investigated. Scanning tunneling spectroscopy (STS) indicates the presence of a two-dimensional electron gas with a binding energy of −160 meV and an effective mass of −0.18 m_e underneath single-layer graphene on the Ir(111) surface. Density functional calculations reveal that the STS features are predominantly due to a hole-like surface resonance of the Ir(111) substrate. Nanometer-sized graphene islands act as local gates, which shift and confine the surface resonance. Funding by the Deutsche Forschungsgemeinschaft via SPP 1459 and SFB 668, the Schleswig-Holstein-Fonds as well as computer time at HLRN are acknowledged.