Strain-Induced Plasmon Confinement in Polycrystalline Graphene
Simone Zanotto, Luca Bonatti, Maria F. Pantano, Vaidotas Mišeikis, G. Speranza, Tommaso Giovannini, Camilla Coletti, Chiara Cappelli, Alessandro Tredicucci, A. Toncelli
Abstract
Terahertz spectroscopy is a perfect tool to investigate the electronic intraband conductivity of graphene, but a phenomenological model (Drude-Smith) is often needed to describe disorder. By studying the THz response of isotropically strained polycrystalline graphene and using a fully atomistic computational approach to fit the results, we demonstrate here the connection between the Drude-Smith parameters and the microscopic behavior. Importantly, we clearly show that the strain-induced changes in the conductivity originate mainly from the increased separation between the single-crystal grains, leading to enchanced localization of the plasmon excitations. Only at the lowest strain values explored, a behavior consistent with the deformation of the individual grains can instead be observed.