Energetics of Stone–Wales defects in deformations of monoatomic hexagonal layers

Stone–Wales (SW) bond rotation and the resulting defect in a hexagonal lattice represent an elementary step in mechanical relaxation. We analyze the energy of such defects and the dependencies on the applied strain magnitude and direction, as well as on the lattice curvature. The results of extensive molecular simulations can be summarized in a single equation for the formation energy. Further, we calculate the interaction between the SW defects and discuss its role in the relaxation process. The atomic structure of transition state and the corresponding barriers are investigated in view of their significance for the rate of SW transformations and therefore the rate of mechanical failure of material.