Stone-Wales defects which often exist in carbon nanotubes (CNTs) and graphene sheets (GSs) can be broke down into pentagon-heptagon (5-7) defect pairs. Using the lattice mechanical model (Peierls-Nabarro model) which considering the effect of periodicity of defects, we will analyze the interaction of 5-7 defect pairs in CNTs. Compare the computational results in this work with the interaction between dislocations according to dislocation theory, and discuss the dependence of radials of CNTs in details. The results show that we can consider 5-7 defect pair as a dislocation and use dislocation theory to solve the problem of interaction between 5-7 defect pairs. The dislocation theory can simplify the simulation of defect pairs in CNTs, and give exactly solution at atomic scale. Based on one slip layer model, we will analyze the distribution of relative displacement on the slip plane and minimizing energy as a function of relative displacement. The minimum energy path will be found by nudged elastic band method. Meanwhile, we find that the interaction of defects plays an important role in the theoretical analysis of defect transformations which strongly effect the stability of CNTs.
