Theory predicted that some topological defects could form via the Stone-Wales transformation in single-walled carbon nanotubes under tension at 2000K, and could act as a dislocation core. Demonstrated here, by means of high-resolution transmission electron microscopy with atomic sensitivity, was the first direct imaging of pentagon-heptagon pair defects in a single-walled carbon nanotube that was heated at 2273K. In situ high-resolution transmission electron microscopic observations revealed an accumulation of topological defects near to the kink of a deformed nanotube. This suggested that dislocation motions or active topological defects were responsible for the plastic deformation of single-walled carbon nanotubes.

Imaging Active Topological Defects in Carbon Nanotubes. K.Suenaga, H.Wakabayashi, M.Koshino, Y.Sato, K.Urita, S.Iijima: Nature Nanotechnology, 2007, 2[6], 358-60