Edge magnetoplasmons in graphene: Effects of gate screening and dissipation

Magnetoplasmons on graphene edges in quantizing magnetic fields are investigated at different Landau-level filling factors. To find the mode frequency, the optical conductivity tensor of disordered graphene in a magnetic field is calculated in the self-consistent Born approximation, and the nonlocal electromagnetic problem is solved using the Wiener-Hopf method. Magnetoplasmon dispersion relations, velocities, and attenuation lengths are studied numerically and analytically while taking into account the screening by metallic gate and the energy dissipation in graphene. The magnetoplasmon velocity decreases in the presence of nearby gates and oscillates as a function of the filling factor because of the dissipation-induced frequency suppression occurring when the Fermi level is located near the centers of Landau levels, in agreement with recent experiments.