Stone–Wales Defect Generation in Carbon Nanotube Being Fractured

Abstract

Quantum-chemistry modeling of carbon nanotubes (8,0) and (5,5) has revealed certain properties of the topochemical Stone–Wales defect. The rolling-up of a planar graphene sheet into a small-diameter nanotube leads to an approximately 0.6 eV decrease in defect formation energy. The SW-defect localized states are resonant with nanotube energy spectrum. In the case of fracture-type deformation, the SW-defect on the compressed side of the tube is energetically favorable. At a fracture angle above critical value–yield point (1.7 deg for (8,0), 2.7 deg for (5,5)), SW-defect appearance decreases the total energy of the tube. Thus, fracturing deformation of the nanotube turns on a plasticity channel in the form of mechanical generation of the Stone–Wales defect.