Mechanism for superelongation of carbon nanotubes at high temperatures.

We report molecular dynamics simulations of the recently discovered superelongation of carbon nanotubes (CNTs) at high temperatures. The nearly simultaneous activation and wide distribution of a large number of defects near the elastic limit play a key role in impeding the formation of localized predominant instability and facilitating large tensile elongation. It suggests new and more complex mechanisms for CNT superelongation in contrast with the previously proposed ideal defect glide and pseudoclimb. Defect interaction and evolution generate multistage necking and kinking and new types of larger defects that dominate the tensile elongation and breaking process. Intricate interplay between CNT sizes and defect nucleation and motion determine the overall deformation pattern.