The Effect of Substituting an X (B, N, O, and F) Atom on the Structural, Magnetic and Optical Properties of Graphene Sheets

The effect of a dopant X atom (X = B, N, O, and F) on the structural, magnetic and optical properties of graphene sheets was investigated through an ab initio study. The induced dipole moment was found to be directed toward atom B in the graphene–B sheet and toward atom C (of graphene) in other dopant sheets due to the charge migration between atoms. This migration arises from the covalent bond between C and X. Both the calculated spin-polarization (P = 8.85%) and the inverse magnetic susceptibility predict that the graphene–O sheet is a weak ferromagnetic material. The electronic specific heat (C) is computed as a function of temperature. The calculated C of the graphene–N sheet offers better thermodynamic properties and higher Debye temperature than the other sheets studied. The optical properties of graphene–X sheets were investigated as a function of energy up to 30 eV. These properties, which prevent the electric field from penetrating the doped graphene sheet, are enhanced upon doping. The graphene–F sheet is found to have the lowest potential to absorb a photon among the sheets, in the region around 11.7 eV. The optical properties of the dopant sheets are improved compared with the pure graphene sheet, suggesting the potential for use in many applications such as antireflective coatings, optical lens coating, optical fiber core, encapsulation of various optical components, and optical adhesives.