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Hydrogenated graphene on Ir(111): A high-resolution electron energy loss spectroscopy study of the vibrational spectrum

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Hydrogen atom adsorption on high-quality graphene on Ir(111) [gr/Ir(111)] is investigated using high-resolution electron energy loss spectroscopy. The evolution of the vibrational spectrum, up to 400 meV, of gr/Ir(111) upon increasing hydrogen atom exposures is measured. The two dominant binding configurations of atomic hydrogen are identified as (1) graphanelike hydrogen clusters on the parts of the graphene more strongly interacting with the Ir(111) surface and (2) dimers bound more weakly to the freestanding parts of the graphene. The graphanelike surface structures lead to increased corrugation of the graphene sheet, yielding graphane-related phonon components. Additionally, a recent theoretical prediction of the existence of a bending character for a LO/TO graphane chair phonon mode is experimentally verified. No clear evidence was found for hydrogen bound on both sides of a high-quality graphene sheet and phonon features strongly suggest interactions between graphanelike hydrogen clusters and Ir atoms in the substrate.

Original languageEnglish
Article number115403
JournalPhysical Review B
Volume93
Issue11
Number of pages9
ISSN2469-9950
DOIs
Publication statusPublished - 4 Mar 2016

    Research areas

  • FREQUENCY-GENERATION SPECTROSCOPY, DENSITY-FUNCTIONAL-THEORY, ADSORPTION, SURFACE, INTERCALATION, ETHYLENE, PT(111), OXYGEN, ABSTRACTION, CARBON

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