Electron–phonon coupling in metal-intercalated graphene

Abstract Platinum-intercalated graphene on a (111)-oriented iridium surface gives rise to a variety of rotational domains with characteristic moiré patterns. Independent of the twist angle subtended by the graphene and substrate lattice, inelastic electron tunnelling spectroscopy reveals elevated graphene phonon excitation only on the intercalated phases. Combining spatially resolved spectroscopy of the electronic structure with non-equilibrium Green’s function simulations highlights the relevance of the balance between elastic and inelastic electron transport for effective phonon creation. The intercalation-induced shift of Fermi level electron density of states from the Brillouin zone centre to its boundary enhances the inelastic channel at the expense of the elastic channel and thereby increases the phonon excitation cross section. The entailed attenuation of the graphene–metal hybridization is reflected by the confinement of Dirac electrons to the tip-induced resonator.