Ab initio density functional theory calculation of 5-7 graphene polymorphs

Abstract

Abstract Three structural varieties of graphene layers consisting of pentagon and heptagon were calculated by the density functional theory method in the generalized gradient approximation. The sublimation energies of 5-7 polymorphs of graphene are 7.49, 7.51, and 7.28 eV/atom for T1, T2, and T3 layer types, respectively. The maximum sublimation energy and the highest stability are observed for the L5-7 T1 layer in which the deformation of the angles between the bonds in the structure as compared to hexagonal graphene is minimal. The conductive properties of layers 5-7 of graphene are metallic, since the band gap at the level of the Fermi energy is zero.