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TT: Fachverband Tiefe Temperaturen

TT 56: Graphene - Preparation and Characterization 1 (jointly with DS, HL, MA, and O)

TT 56.8: Talk

Thursday, March 14, 2013, 12:15–12:30, H17

Phonons of graphene on Ir(111) — •Michael Endlich¹, Alejandro Molina-Sánchez², Ludger Wirtz², and Jörg Kröger¹ — ¹Institut für Physik, Technische Universität Ilmenau, D-98693 Ilmenau — ²Physics and Material Sciences Research Unit, University of Luxembourg, L-1511 Luxembourg

The phonon dispersion relations of graphene on Ir(111) were determined with angle-resolved inelastic electron scattering. A weak graphene–Ir interaction is inferred from the lifting of the degeneracy of the out-of-plane optical and acoustic dispersion branches at the K point of the surface Brillouin zone and from the energy reduction of the out-of-plane optical phonon. Despite this interaction the Kohn anomalies known from graphite of the highest optical phonon branch at Γ and K persist. The experimental dispersion relations are in agreement with density functional calculations.