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Download fileMonolayer and Bilayer Graphene on Ru(0001): Layer-Specific and Moiré-Site-Dependent Phonon Excitations
journal contribution
posted on 19.07.2021, 20:29 authored by Johannes Halle, Nicolas Néel, Jörg KrögerGraphene phonons
are excited by the local injection of electrons
and holes from the tip of a scanning tunneling microscope. Despite
the strong graphene–Ru(0001) hybridization, monolayer graphene
unexpectedly exhibits pronounced phonon signatures in inelastic electron
tunneling spectroscopy. Spatially resolved spectroscopy reveals that
the strength of the phonon signal depends on the site of the moiré
lattice with a substantial red-shift of phonon energies compared to
those of free graphene. Bilayer graphene gives rise to more pronounced
spectral signatures of vibrational quanta with energies nearly matching
the free graphene phonon energies. Spectroscopy data of bilayer graphene
indicate moreover the presence of a Dirac cone plasmon excitation.