▎ 摘　　要

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 investi-gation, 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.