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Stone-Wales
defect
dynamics in graphene and carbon nanotubes
Superplasticity in sp2 hybridized
carbon molecules such as graphene and nanotubes is thought to be
related to the dynamics of crystalline imperfections, specifcally
Stone-Wales defects. The behavior of Stone-Wales defects at long
time-scales is investigated using a kinetic Monte Carlo (KMC)
technique. The potential energy surface for the KMC calculation is
computed either with a continuum theory or directly calculated through
empirical potentials. Our study has identified that, in addition to a
conventional glide mechanism, plastic deformation may also occur due to
an alternating dislocation array under high applied stresses. The
stability of the different deformation mechanisms depends on local
stress and strain fields, which may significantly distort the defect
core. A simulation of nanoindentation of a graphene sheet is reproduced
below.
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References
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1. E.
Ertekin, M. S. Daw and D. C. Chrzan, Elasticity theory of topological
defects in carbon nanotubes and graphene. Philosophical Magazine
Letters 88 (2) 157-167, 2008.
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