title: Phonon dispersion of quasi-freestanding graphene on Pt(111).
abstract: High-resolution electron energy loss spectroscopy has been used to probe phonon dispersion in quasi-freestanding graphene epitaxially grown on Pt(111). Loss spectra clearly show different dispersing features related to both acoustic and optical phonons. The present results have been compared with graphene systems which strongly interact with the substrate, i.e. the nearly-flat monolayer graphene (MLG)/Ni(111) and the corrugated MLG/Ru(0001). We found that the phonon dispersion of graphene/Pt(111) reproduces well the behavior of pristine graphite. This could be taken as an indication of the negligible interaction between the graphene sheet and the underlying Pt substrate. The softening of out-of-plane modes observed for interacting graphene/metal interfaces does not occur for the nearly-free-standing graphene/Pt(111).
authors.affiliation: Dipartimento di Fisica, Università degli Studi della Calabria, 87036 Rende (Cs), Italy. antonio.politano@fis.unical.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Politano
authors.forename: Antonio Raimondo
authors.initials: AR
authors.lastname: Marino
authors.forename: Gennaro
authors.initials: G
authors.lastname: Chiarello