First principles study of electronic structure and optical properties of beryllium nitride in β phase (β-Be3N2)

Within the framework of density functional theory, electronic structure of beryllium nitride in β phase (β-Be3N2) is determined, and on the base of the electric structures, a number of key optical properties of β-Be3N2 are calculated, with the method of full-potential linearized augmented plane wave under the random phase approximation for the boundaries and the generalized gradient approximation for the exchange-correlation potentials. The calculated optical properties as a function of frequency include the real and imaginary parts of the dielectric function ε(ω), the refraction index n(ω), the extinction coefficient κ(ω), the reflectivity R(ω), the energy loss function L(ω), and the absorption coefficient I(ω) along the a and c directions of the primitive cell presenting the β-Be3N2 crystals. It is demonstrated that the optical properties of β-Be3N2 appear anisotropic for energies <35 eV, within the range of ultraviolet, and the p orbitals of nitrogen play the major role in relevant optical transitions.