The magnetic response of graphene split-ring metamaterials

Graphene has emerged as a promising platform for THz plasmonics,allowing high confinement,long lifetimes and fast electrical tunability.Here,we predict a strong magnetic dipole response by graphene split nanorings at THz frequencies,allowing the attainment of metamaterials with a high degree of field confinement(approximately one hundredth of the excitation wavelength)that is not reachable with conventional noble metals.The magnetic response of highly doped graphene split-rings in the far-infrared is much stronger than that displayed by gold structures of similar thicknesses.We further explored stacked graphene layers as a practical way of producing high-frequency magnetism in thin,electrically tunable metamaterials.Our results support the great potential of using graphene to achieve electrically tunable magnetic metamaterials.