Ab initio study of dielectric response of rippled graphene

Ab initio calculations of dielectric function and electron energy loss (EEL) function of periodically rippled armchair-edged graphene were performed in the framework of the random-phase approximation. The bending of graphene was found to remove restrictions on the electron transitions being forbidden in the flat graphene for certain light polarization. As a result, new peaks appear in the optical absorption spectrum and EEL spectrum of rippled graphene. Energy position, intensity, and width of the peaks are sensitive to the height of out-of-plane graphene bending that can be used in construction of graphene-based materials with variable transparency window.