Graphene polymorphs

Abstract

Abstract Ab initio calculations of twelve structural varieties of graphene were carried out using the density functional theory method. The structure of non-hexogonal graphene species contains topological defects 4, 5, 7, 8, 10, or 12, which deform the layers. The sublimation energy of graphene polymorphs decreases with increasing degree of layer structure deformation compared to hexagonal graphene. In the electronic structure of graphene layers L4-12 and L4-6-8e at the Fermi level, there are band gaps 0.59 and 0.37 eV wide, so these layers must be semiconductors.