The graphitic sheet of group III-nitrides are a subject of interest due to their novel technological applications. In this paper, we focus on GaN graphitic sheet, investigating its electronic and optical properties in the framework of density functional theory. The optical properties of the GaN graphitic sheet such as dielectric function, refraction index, electron energy loss function, reflectivity, absorption coefficient, optical conductivity and extinction index are calculated for both parallel and perpendicular electric field polarizations. The results show that the optical spectra are anisotropic along these two polarizations. Optical conductivity for (E|x) and (E|z) is zero when the energy is <2.14 and 3.98 eV, respectively; which confirms that GaN graphitic sheet has semiconductor property.
