Theoretical investigation of the structural, electronic, elastic and optical properties of the new layered ternary chalcogenide tetragonal compounds Cu₂MX₄ (M = W and Mo; X=S and Se)

Ternary transition metals chalcogenides (TMC) have attracted a lot of interest in recent years because of their various technological applications, particularly solar energy, photocatalysis, and batteries. In this paper, structural, electronic, elastic, and optical properties of I–Cu₂MX₄(M ​= ​W, Mo; X ​= ​S, Se) are studied using ab initio computation. Furthermore, the calculated results of lattice constants are in agreement with available experimental results. The studied compounds are semiconductors with indirect band gap nature. Moreover, population analysis is used to assess the nature of the chemical bonds. The calculated elastic constants indicate that our materials are brittle and mechanically stable by satisfying the condition of stability. Frequency-dependent linear optical properties are also investigated such as refractive index and absorption coefficient for incident electromagnetic radiation polarized parallel to the three principal crystalline directions and show good absorption coefficients in the ultraviolet region. All obtained results agree well with available theoretical and experimental data.