Strong terahertz conductance of graphene nanoribbons under a magnetic field

We demonstrate that the optical response of graphene nanoribbons in the terahertz to far-infrared regime can be significantly enhanced and tuned by an applied magnetic field. The dependence of the threshold frequency on the magnetic field is studied. The ribbons with the strongest terahertz conductance under a magnetic field are those with one-dimensional massless Dirac Fermion energy dispersion. For a given ribbon, there exists an optimal field under which the conductance resonance can occur at the lowest frequency. (C) 2008 American Institute of Physics.