Disorder and screening in decoupled graphene on a metallic substrate

We report the coexistence of charge puddles and topographic ripples in graphene decoupled from the Ir(111) substrate it was grown on. We show the topographic and the charge disorder to be locally correlated as a result of the intercalation of molecular species. From the analysis of quasiparticle scattering interferences, we find a linear dispersion relation, demonstrating that graphene on a metal can recover its intrinsic electronic properties. The measured Fermi velocity v(F) = 0.9 +/- 0.04x10(6) m/s is lower than in graphene on dielectric substrates, pointing to a strong screening of electron-electron interactions in graphene by the nearby metallic substrate.