| Description |
We investigated one-dimensional plasmon propagation in bilayer graphene under the effect of in-plane electric field E0. Because of the gapless nature of graphene spectrum the applied electric field can induce separation of charges creating a p-n junction that split the width of the flake into positively and negatively charged halves. The fluctuations of the induced charge density and nonhomogeneity of charge distribution across the width of the flake underlie the propagation of one-dimensional plasmon along the p-n junction. The flake dimensions and electric field were chosen large enough to allow semiclassical treatment through the approximation of charge carriers as 2D fluid and the use of hydrodynamic model to obtain the dispersion relations. In the limit of short wavelength, even modes had higher energies than odd ones. Surprisingly, that behavior was reversed with the first even mode becoming the lowest mode in the limit of long wavelengths. In all cases the plasmon spectra were proportional to √E0. We considered a second case where an additional perpendicular electric field was applied through a gate. In that case, the additional field created a gap in the spectrum of graphene resulting in a neutral strip along the flake. The spectrum was linear in electric field E0 indicating more sensitivity to the applied field in gated bilayer than in gapless case. |
