Modeling of an ultrahigh-frequency resonator based on the relative vibrations of carbon nanotubes

An ultrahigh frequency resonator based on the relative vibrations of the walls of carbon nanotubes is proposed and studied theoretically. Density functional theory is used to compute the energy of interaction of the walls as a function of their relative rotation and displacement along the principal axis of nanotube. The computed energy curves are fitted analytically and further exploited in the calculations of the frequencies of small relative axial and rotational vibrations of the walls. For a model resonator based on the (9,0)@(18,0) double-walled carbon nanotube with the movable outer wall, the microcanonical molecular dynamics simulations are performed to predict the quality factor of the resonance. Possible applications of the resonator are suggested, which include nanoscale mass detection. The estimated mass sensitivity of the proposed system reaches the atomic-mass limit at liquid-helium temperature.