Carbon has diverse structures both in nature or in laboratory.[1,2] Three dimensional diamond and two dimensional graphite sheet are the two well known forms. Within the past ten or so years, the discoveries of bucky balls (0-dimensional) and bucky tubes (1-dimensional) have generated great interest among scientists and technologists alike. Studies of the structures and properties of low dimensional carbon molecules show tremendeous potential for use in nanoscale electronic devices.[3-4] Motivated by these exciting possibilities in finding new forms of carbon materials and their potential applications, we designed hypothetical carbon molecules, namely carbon nano-toroids. Carbon toroids are also ideal in studying the elastic and plastic deformation behavior of nanotubes under bending loads. We can accurately correlate the behaviour of the tubes to its uniform curvature. In a futuristic point of view, pure or doped (inside the tube by other elements) forms of carbon toroids could be synthesized and may find its use as components of electromagnatic devices or micromachines, e.g. nanocundicting rings as a part of electromotor.
The carbon toroids can be characterized by three integers (n,m,l) where (n,m) define the single walled carbon nanotube, whereas l is the smallest repeat unit along the tube axis. In this particular work we focused on the toroids of (10,10) tubes and studied their energetics, structure and mechanical properties as a function of their toroidal radius. Especially important, we have observed specific strain release paths for the toroids, i.e. the toroids going through plastic deformations and nucleating a number of kinks. We have studied phase stability diagram of toroids with kinks as a function of toroidal radius.
Hoffman DR, Physics Today 44, 22-29 (1991)
Tibbets GG, J. Cryst. Growth 66, 632-8 (1984)
Dai H, Wong EW, Lieber CM, Science 272, 523 (1996)
Wong EW, Sheehan PE, Lieber CM, Science 277, 1971 (1997)
California Institute of Technology, Materials and Process Simulation Center and Division of Chemistry and Chemical Engineering
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