Optical properties of simple hexagonal and rhombohedral few-layer graphenes in an electric field

Abstract

The influence of a perpendicular electric field (F) on the optical properties of simple hexagonal and rhombohedral few-layer graphenes is studied through the tight-binding model. The electric-field-modulated absorption spectra depend on the stacking sequence. The low-energy absorption spectra of simple hexagonal few-layer graphenes exhibit the jumping structures in the absence or presence of an electric field. On the other hand, absorption spectra of rhombohedral few-layer graphenes show discontinuities and sharp peaks at F=0. Besides, the application of F affects the absorption spectra, generates new peaks, and changes peak position and peak height. The frequency of the peak is predicted to be closely associated with the stacking sequences and the field strength. Above all, the predicted absorption spectra could be verified by optical measurements.