Torsional strain energy evolution of carbon nanotubes and their stability with encapsulated helical copper nanowires

Torsional strain energy evolution of a single-walled carbon nanotube (CNT) and torsional stability of a CNT encapsulating a helical copper nanowire are investigated by molecular dynamics simulations. The strain energy transfer of the pristine CNT reveals a unique wave-like mode along the torsional axis and afterwards isoenergetic strips form helical distributions in the vicinity of the critical point. Ripples appear together with structural buckling and strain energy release at the buckling point. Although the insertion of a copper nanowire impedes abrupt structural buckling and increases the stability of the CNT, the increase depends greatly on the number of the metal atoms. This kind of hybrid would increase the critical torsional angle and the maximum torque of the corresponding CNT in the future application of nano-mechanical devices.