Energetics and Structure of Single Walled Carbon Nanotoroids
Guanghua Gao, Tahir Cagin*, and William A. Goddard III
Materials and Process Simulation Center,
California Institute of Technology,
Pasadena, CA, 91125
This is an abstract
for a poster given at the
Foresight Conference on Molecular Nanotechnology.
There will be a link from here to the full article when it is
available on the web.
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.
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Wong EW, Sheehan PE, Lieber CM, Science 277, 1971 (1997)