Ab Initio Modeling of the Electronic and Energy Structure and Opening the Band Gap of a 4p-Element-Doped Graphene Monolayer

Abstract

In this paper, we study the electronic and band structure of 4p-elements (M = Ge, Si)-doped graphene nanosheets with vacancies by the density functional theory method. The adsorption energy of the doping atoms and the relative stability of doped graphene monolayers are estimated. An antiferromagnetic ordering is discovered in these graphene-based systems. Based on the analysis of the electronic populations of atomic orbitals according to Mulliken, the states’ densities in graphene systems are calculated. The equilibrium parameters of the electronic structure of graphene nanosheets are obtained. The regularities of changes in the electronic structure of the valence band and the induction of an energy gap in M-doped graphene monolayers containing vacancies are studied. The features of the electronic structure near the Fermi level, as well as the role of the structural effect in opening the energy gap in graphene–M systems, are discussed. Doping with 4p elements opens the energy gap in graphene–Ge(Si) systems. The local magnetic moments for antiferromagnetic ordering are estimated on carbon atoms of graphene nanosheets including Ge(Si). The calculated values ​​of the local magnetic moments on carbon atoms in graphene–M (Ge, Si) systems are comparable with each other.