Theoretical modeling of experimental HREEL spectra for supported graphene

We present a simple model for the resonant feature designated as the π plasmon in single-layer graphene supported by a metal substrate, which is excited via high-resolution electron energy loss spectroscopy (HREELS) in the off-specular scattering geometry. Using a two-dimensional, two-fluid hydrodynamic model for interband transitions of graphene's π and σ electrons and an empirical Drude–Lorentz model for the metal in the local approximation enables us to reproduce, at the qualitative and semi-quantitative levels, the typical experimental features of the HREEL spectra in the visible to the ultraviolet frequency range. - Highlights: • We present an analytical model for the HREELS of graphene/metal system. • We use the 2D, two-fluid hydrodynamic model for graphene's π and σ electrons. • We use a simple dielectric function of the Drude–Lorentz type for a metal substrate. • HREEL spectra are well reproduced qualitatively and semi-quantitatively