Dislocation dipole movement in graphene at finite temperatures: Molecular dynamics study

Using of molecular dynamics modeling, the effects of temperature on the movement of dislocations in graphene are studied for several types structural defects - Stone-Wales (or a dipole with a zero shoulder) and dislocation dipoles 5-7 with arm lengths 7, 9.3, and 11.5 Å. It is found that dislocation dipoles remain stable at temperatures below 1400 K. An increase in temperature leads to the movement of dislocation dipoles either towards each other (typical for all studied dipoles), or in the opposite direction (only for dipoles with arm lengths of 9.3 and 11.5 Å). When dislocations move towards each other, their annihilation can occur due to a simple rotation of the C-C bond. It is shown that the arm length 9.3 Å is close to the equilibrium value at which dislocation annihilation is not observed.