Selective nonresonant excitation of vibrational modes in suspended graphene via vibron-plasmon interaction

Artikel i vetenskaplig tidskrift, 2015

We theoretically study a doped graphene ribbon suspended over a trench and subject to an ac-electrical field polarized perpendicularly to the graphene plane. In such a system, the external ac-field is coupled to the relatively slow mechanical vibrations via plasmonic oscillations in the isolated graphene sheet. We show that the electrical field generates an effective pumping of the mechanical modes. It is demonstrated that in the case of underdamped plasma oscillation, a peculiar kind of geometrical resonance of the mechanical and plasma oscillations appear. The efficiency of pumping significantly increases when the wavenumber of the mechanical mode is in close agreement with the wavenumber of the plasma waves. The intensity of the pumping increases with the wavenumber of the mode. This phenomenon allows selective actuation of different mechanical modes, although the driving field is homogeneous.