LAUSR

Abstract The crystal structures, electronic, elastic and optical properties of the ternary compounds CuSbS 2 and CuBiS 2 have been investigated by using the full-potential linear augmented plane wave (FP-LAPW) method. From this study, it is found that the compounds CuSbS 2 and CuBiS 2 have indirect band gap energies which are calculated with the mBJ potential as 1.28 and 1.05 eV, respectively. CuSbS 2 crystallizes in an orthorhombic structure, with the Pnma space group, the lattice parameters are a = 6.018 A, b = 3.795 A and c = 14.495 A, CuBiS 2 has also an orthorhombic structure, with the space group Pnma and the lattice parameters a = 6.134 A, b = 3.911 A and c = 14.548 A, which are used in our calculations. Optical parameters, such as dielectric constant, refractive index and reflectivity are calculated and analyzed. Elastic properties are also investigated for the first time. The results demonstrated that the compounds CuSbS 2 and CuBiS 2 have the potential to be used for photovoltaic applications.