Periodic spatial variation of the electron-phonon interaction in epitaxial graphene on Ru(0001

TL;DR

This study uses low-temperature scanning tunnelling spectroscopy to reveal spatial variations in electron-phonon interactions in epitaxial graphene on Ru(0001), linked to local lattice mismatch effects.

Contribution

It demonstrates the spatial inhomogeneity of electron-phonon interactions in graphene on Ru(0001) due to lattice mismatch-induced local variations.

Findings

Inelastic feature at 360 meV related to vibrational mode

Spatial variation in differential conductance due to electron-phonon interaction

Inhomogeneity caused by local lattice mismatch effects

Abstract

We have performed low temperature scanning tunnelling spectroscopy (STS) measurements on graphene epitaxially grown on Ru(0001). An inelastic feature, related to the excitation of a vibrational breathing mode of the graphene lattice, was found at 360 meV. The change in the differential electrical conductance produced by this inelastic feature, which is associated with the electron-phonon interaction strength, varies spatially from one position to other of the graphene supercell. This inhomogeneity in the electronic properties of graphene on Ru(0001) results from local variations of the carbon-ruthenium interaction due to the lattice mismatch between the graphene and the Ru(0001) lattices.