Strong terahertz conductance of graphene nanoribbons under a magnetic field

We demonstrate that the optical response of graphene nanoribbons in the terahertz to far-infraredregime can be significantly enhanced and tuned by an applied magnetic field. The dependence of thethreshold frequency on the magnetic field is studied. The ribbons with the strongest terahertzconductance under a magnetic field are those with one-dimensional massless Dirac Fermion energydispersion. For a given ribbon, there exists an optimal field under which the conductance resonancecan occur at the lowest frequency.