▎ 摘　　要

The electronic and the linear optical properties of a monolayer B2C graphene sheet are investigated through the density functional theory. The dielectric tensor is derived within the random phase approximation (RPA). Specifically, the dielectric function, absorption coefficient, optical conductivity, extinction index, loss function, reflectivity, and the refraction index of the monolayer B2C graphene sheet are calculated for both parallel and perpendicular electric field polarizations. The results show that the optical spectra are anisotropic along these two polarizations. For the electric field parallel to monolayer B2C graphene E parallel to x, adding the intraband transitions contribution, will change the optical spectra of a monolayer B2C graphene sheet significantly, while in the electric field perpendicular to monolayer B2C graphene E parallel to z did not change. Adding the intraband transitions contribution shows that the dielectric function has singularity at zero frequency because of the metallic behavior of a monolayer B2C graphene sheet. Also by considering the intraband transitions contribution for energy loss function in the electric field parallel to monolayer B2C graphene, the first plasmon frequency peak has been shifted from 2.76 eV to 4 eV. Crown Copyright (C) 2012 Published by Elsevier Ltd. All rights reserved.