First-principles prediction on elastic anisotropic, optical, lattice dynamical properties of ZnGeP2

Abstract

The elastic anisotropic, band structure, optical and lattice dynamical properties of ZnGeP2 have been investigated via density functional theory and density functional perturbation theory. The calculated lattice constants and elastic constants of ZnGeP2 are in good agreement with the previous results. The anisotropy in elasticity has been visualized by three-dimensional surfaces and the planar projection contours. ZnGeP2 shows an obvious elastic anisotropy under zero pressure, and the anisotropy increases with the increase in pressure. The hybrid functional HSE06 is used to evaluate the electronic properties of ZnGeP2, and the results suggests that the HSE06 hybrid functional can obtain more reasonable band structure. ZnGeP2 shows direct band gap of 2.06 eV. In addition, the optical spectrum is derived for photon energies up to 40 eV. The phonon frequencies at the Brillouin zone center are calculated and discussed.