High-energy collective electronic excitations in free-standing single-layer graphene

Abstract : In this joint experimental and theoretical work, we investigate collective electronic excitations (plasmons) in free-standing, single-layer graphene. The energy- and momentum-dependent electron energy-loss function was measured up to 50eV along two independent in-plane symmetry directions (ΓM and ΓK) over the first Brillouin zone by momentum-resolved electron energy-loss spectroscopy in a transmission electron microscope. We compare our experimental results with corresponding time-dependent density-functional theory calculations. For finite momentum transfers, good agreement with experiments is found if crystal local-field effects are taken into account. In the limit of small and vanishing momentum transfers, we discuss differences between calculations and the experimentally obtained electron energy-loss functions of graphene due to a finite momentum resolution and out-of-plane excitations.
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Contributor : Gaëlle Bruant <>
Submitted on : Wednesday, January 15, 2014 - 10:18:45 AM
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P. Wachsmuth, R. Hambach, Mk Kinyanjui, Matteo Guzzo, G. Benner, et al.. High-energy collective electronic excitations in free-standing single-layer graphene. Physical Review B : Condensed matter and materials physics, American Physical Society, 2013, 88, pp.075433. ⟨10.1103/PhysRevB.88.075433⟩. ⟨hal-00931224⟩



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