The optoelectronic, elastic and magnetic properties of Iron and Rhodium doped NbTu₂S₄ Sulvanite semiconductors: promising candidates for next-generation energy harvesting devices

The family of ternary Chalcogenides systems has been investigated for their potential applications in optoelectronic devices. We present first-principles calculations of structural, elastic, magnetic, optical properties, and the effective mass of the Sulvanite compounds NbTu₂S₄ (Tu = Fe, Rh) is determined by GGA + U. The electronic band gaps are NbFe₂S₄ (2.4 eV (up)/1.8 eV (dn) and NbRh₂S₄ (2.07 eV (up)/1.6 Ev (dn), which are comparable to other computed results. Optical properties such as absorption coefficient, dielectric function, energy loss function, reflectivity function, refractive index, and extinction coefficient have been calculated for the first time. There is no difference between the materials regarding transparency in the visible range. The low hole effective mass and high valence band indicate a P-type material with photovoltaic applications. Plasma frequencies are observed around 13 eV for both investigated crystals. Sulvanite crystals have effective masses computed from high symmetry points varying non-linearly. The elastic parameter was used to study elastic properties. It is observed that both crystals show an anisotropic nature and ductility. The optical properties suggest that these crystals could be suitable for optoelectronic devices.