摘要

Four ternary semiconductors with the chalcopyrite structure (BeCN2, BeSiN2, MgCN2, and MgSiN2) were studied using the first principles methods. Their structural, electronic, optical and elastic properties were calculated. All these materials were found to be the indirect band gap semiconductors, with the calculated band gaps in the range from 3.46 eV to 3.88 eV. The degree of covalency/ionicity of the chemical bonds in these compounds was compared. Anisotropy of the optical properties of these tetragonal crystals was demonstrated by calculating the real and imaginary parts of the dielectric function epsilon. Anisotropy of the elastic properties of these materials was analyzed by plotting the three-dimensional surfaces of the Young moduli and their two-dimensional cross sections. It was also shown (at least, qualitatively) that there exists a correlation between the optical and elastic anisotropy: the most optically anisotropic MgSiN2 is also most elastically anisotropic material in the considered group. High hardness (bulk moduli up to 300 GPa) together with large band gaps may lead to new potential applications of these compounds.