Probing plasmons on the edge of graphene nanoribbons under electric field

By using first principle method, we address the plasmon excitation in narrow zigzag and armchair graphene nanoribbons under the effect of the perpendicular electric field. We observed that the edge plasmons with very high one-dimensional confinement mainly originated from π transition peaks and along with increasing the ribbon width, edges contribute much less than in narrow ribbons. Applying electric field excites and hybrids distinct plasmon modes which indicate, the magnitude, intensity and type of plasmon modes within various momentum transfer range are dependent differently on the gating. The key role of charge polarization at the edge and surface plasmons is discussed in the presence of electric field based on the evolution of the dielectric function. Confined edge and surface plasmon modes change under electric field makes graphene nanoribbons a suitable candidate for new terahertz plasmonic applications.