Ab initio study on the structural and electronic properties of Li_3GaP_2 compared with Li_3GaN_2

摘要

Structural and electronic properties of Li_3GaP_2 and Li_3GaN_2 have been investigated by the first-principles calculations within the density functional theory. The calculated lattice parameters of the two compounds are in excellent agreement with the available experimental data. Both Li_3GaP_2 and Li_3GaN_2 are direct band gap semiconductors with the band gaps of 1.26 eV and 2.37 eV, respectively. The Ga—P (Ga—N) and Li—P bonds consist of a mixture of ionic character and covalent nature, while the Li—N bond exhibits almost ionic. The bonds in the Li_3GaP_2 are shown to have stronger covalency and weaker ionicity as compared to the corresponding ones in the Li_3GaN_2.