4 research outputs found
Nanotube-Based NEMS: Control vs. Thermodynamic Fluctuations
Multi-scale simulations of nanotube-based nanoelectromechanical systems
(NEMS) controlled by a nonuniform electric field are performed by an example of
a gigahertz oscillator. Using molecular dynamics simulations, we obtain the
friction coefficients and characteristics of the thermal noise associated with
the relative motion of the nanotube walls. These results are used in a
phenomenological one-dimensional oscillator model. The analysis based both on
this model and the Fokker-Planck equation for the oscillation energy
distribution function shows how thermodynamic fluctuations restrict the
possibility of controlling NEMS operation for systems of small sizes. The
parameters of the force for which control of the oscillator operation is
possible are determined.Comment: 40 pages, 12 figure
Effect of Peierls transition in armchair carbon nanotube on dynamical behaviour of encapsulated fullerene
The changes of dynamical behaviour of a single fullerene molecule inside an
armchair carbon nanotube caused by the structural Peierls transition in the
nanotube are considered. The structures of the smallest C20 and Fe@C20
fullerenes are computed using the spin-polarized density functional theory.
Significant changes of the barriers for motion along the nanotube axis and
rotation of these fullerenes inside the (8,8) nanotube are found at the Peierls
transition. It is shown that the coefficients of translational and rotational
diffusions of these fullerenes inside the nanotube change by several orders of
magnitude. The possibility of inverse orientational melting, i.e. with a
decrease of temperature, for the systems under consideration is predicted.Comment: 9 pages, 6 figures, 1 tabl