Orbiting atoms and C[sub 60] fullerenes inside carbon nanotori

Abstract

The discovery of carbonnanostructures, such as carbon nanotubes and C₆₀fullerenes, has generated considerable interest for potential nanoelectronic applications. One such device is the high frequency nanoscale gigahertz oscillator. Several studies investigating these oscillators demonstrate that sliding an inner-shell inside an outer-shell of a multiwalled carbon nanotube generates oscillatory frequencies in the gigahertz range. Research has shown that the oscillation is sensitive to the diameter and the helicity of the tube and that the inner tube length can be used to tune the frequency, such that the smaller the inner tube length the higher the frequency of oscillation, suggesting that a C₆₀fullerene might provide the ultimate core. Recently, researchers have observed single continuous toroidal nanotubes with no beginning or end, effectively a single-walled carbon nanotube closed around onto itself so that the two open ends fuse together, stabilized by van der Waals forces alone, to form a perfect “nanotorus.” The question arises as to whether it is possible to create a C₆₀- nanotorusoscillator or orbiter, comprising a C₆₀fullereneorbiting around the inside of a nanotorus. The C₆₀- nanotorusorbiter has yet to be constructed and the aim here is to assess its feasibility by examining the dominant mechanics of this potential nanoscale device. As in previous studies, the Lennard-Jones potential is used to calculate the interatomic forces acting on the fullerene due to the nonbonded interactions. Furthermore, other relevant forces are examined. Initially, we investigate the dynamics of an orbiting single atom followed by the corresponding analysis for an orbitingC₆₀fullerene. The equilibrium position depends on the radius of the nanotorus tube for both the atom and the C₆₀fullerene. Gravity is shown to be negligible, while the centrifugal forces are shown to move the orbiting body further from the center of the nanotorus. The theory also predicts that by changing the orbital position, the resulting frequencies, which are in the gigahertz range, may vary to as much as four times those obtained for the C₆₀-nanotubeoscillator.