Magneto-optical properties of armchair nanographene ribbons under spatially modulated electric field

The spatially modulated electric field is used to tune the magneto-optical properties of an armchair nanographene ribbon. The band structure and optical absorption spectrum under the perpendicular magnetic field and the spatially modulated electric field are calculated through the tightbinding model and the gradient approximation. The quasi-Landau levels are greatly affected by the periodic potential such as the modulation of the energy dispersion, the creation of the extra band-edge states, and the alteration of the Landau wave functions. The modulation ability of the electric field grows with the increase of the electric field strength or the decrease of the periodic length. The change of the electronic properties is directly reflected in the optical absorption spectra. The number, the shape, the intensity, and the position of the absorption peaks are altered. The selection rule of the optical excitations between the quasi-Landau levels is destroyed under the influence of the modulated electric field. The predicted results can be directly verified by optical measurements.