Computational modelling of structural, mechanical, and optoelectronic features of chalcogenides VIn₃X₄ (X = S, Se)...

Current study explored structural, optoelectronic, and thermodynamics characteristics of VIn₃X₄ (X = S, Se) compounds utilizing first-principles density functional theory (DFT) computations with CASTEP. The generalized gradient approximations with Perdew-Burke-Ernzerhof functional (GGA-PBE) was used to model exchange-correlation effects. Band structure analysis confirmed the semiconducting nature of both materials. The calculated bandgaps, determined using the GGA-PBE and HSE03 functional, were 1.64 eV and 1.34 eV for VIn₃S₄, and 0.99 eV and 0.94 eV for VIn₃Se₄, respectively. All bandgaps were found to be direct. Mechanical stability is found for VIn₃S₄ and VIn₃Se₄ under Born stability criterion. Pugh's ratio and Poisson's ratio are determined, indicating ductile nature for both materials. Thermodynamic attributes of these chalcogenides were assessed, revealing Debye temperatures of 1037 K and 1195 K for VIn₃S₄, and VIn₃Se₄, respectively. Moreover, these materials unveiled robust optical absorption across visible and ultraviolet ranges. A detailed examination of optical properties, containing dielectric functions, loss function, refractive indices, extinction co-efficient, reflectivity, and optical conductivity, were achieved within an energy range of 0.0-24 eV. The outcomes demonstrated anisotropic polarization in all both compounds, proposing their potential for optoelectronic applications.