Comprehensive analysis of the phase stability, optoelectronic, mechanical, thermodynamic, and vibrational properties for prospective optoelectronic applications of novel combinations of chalcogenides XScTe2 (X = Li, Rb) by employing density functional theory

Optoelectronic devices are being extensively employed nowadays that are vital to diverse range of the appliances. The exploration of apposite materials for such efficient devices appears to be challenging. So, this study recommends novel combinations of chalcogenides as high energy materials that are seldom ever described. Here, density function theory (DFT) is employed to analyze the phase stability, optoelectronic, mechanical, thermodynamic, and vibrational properties of tellurium-based ternary chalcogenides XScTe2 (X = Li, Rb) by utilizing Perdew-Burke-Ernzerhof-generalized gradient approximation (PBE-GGA) and HSE06 through CASTEP simulation code. The observed minimum magnitude of free energy for these structures is found to be well-consistent with the stability requirements of the thermodynamics that confirms their chemical stability. The indirect energy band gap declares them semiconductors. Significant absorption is noticed in the ultraviolet (UV) range of the electromagnetic spectrum. The mechanical properties determined through Voigt-Reuss-Hill approximation determine mechanical instability due to the appearance of some negative elastic constants. Pugh's ratios evaluated as larger than 1.75 while demonstrating its ductile nature. The comprehensive analysis of thermodynamic behavior declares that these are thermodynamically stable materials. The density functional perturbation theory (DFPT) delineates no imaginary frequencies signifying both these compounds as stable materials. The thorough examination suffices to identify these materials as effective ones for optoelectronic uses.