Stratified Graphene-Noble Metal Systems for Low-Loss Plasmonics Applications
Anna L. Rast, Timothy Sullivan, Vinod K. Tewary
We demonstrate numerically that bulk plasmon losses in noble metal films can be significantly reduced through the addition of a graphene coating and hexagonal boron nitride substrate. Silver films with a trilayer graphene coating and hBN substrate demonstrated surface plasmon-dominant spectral profiles for metallic layers as thick as 34nm. A continued fraction expression for the effective dielectric function, which includes boundary interactions, is used to systematically demonstrate plasmon peak tunability for a variety configurations. Variations include substrate, plasmonic metal, and individual layer thickness for each material. Mesoscale calculation of electron energy loss spectra is performed using individual layer dielectric functions as input to the effective dielectric function calculation, from which the loss spectra are directly determined.