Thermal stability of twin graphene: A Reaxff molecular dynamics study

Twin graphene, a new phase of two-dimensional semiconducting carbon allotrope, is theorized to exist and show a great deal of potential applications due to its superior electronic and mechanical properties. In this investigation, the thermal stability of twin graphene is explored via molecular dynamic (MD) simulations based on a reactive force field (ReaxFF). We show that, before twin graphene totally transforms into amorphous graphene, the initial structural evolution of twin graphene shows unique behavior that leads to a mesophase consisting of amorphous graphene, carbon atom chains and complex structures from 1500 to 1700 K. In particular, a new twin structure, named v-twin graphene, is observed in the mesophase. Detailed simulations show that v-twin graphene possesses a more stable molecular structure than the original twin graphene. These findings provide fundamental understandings for the thermal stability and structural evolution of these two types of twin graphene.