Exploring Quaternary Heusler Compounds CoRuXSb (X: Ti, Zr): A Path to Thermoelectric and Optoelectronic Innovation

This paper analyzes the structural, electronic, elastic, thermodynamic, optical and thermoelectric properties of Heusler quaternary compounds CoRuXSb (X: Ti, Zr) using first-principles calculations with the ab initio linearized augmented plane waves at full potential (FP-LAPW) method via the Wien2k code, using density functional theory (DFT) with the TB-mBJ-[Formula: see text] approximation. These compounds are found to be more stable in the ferromagnetic phase with a type-1 structure and adopt semiconducting behavior in both spin states. The TB-mBJ approximation, which is close to the experimental results, reveals that CoRuTiSb and CoRuZrSb have indirect band gaps in both spin channels, but CoRuTiSb has a direct band gap in the down-spin channel. Thus, these compounds are classified as semiconducting in both spin states. Negative formation energies ([Formula: see text]) and positive cohesion energies ([Formula: see text]) indicate thermodynamic stability resulting in strong atomic bonds. Similarly, their dynamic stability is proven by the positive phonon frequencies. Mechanical stability criteria confirm their robustness, while the [Formula: see text] ratio according to the PUGH testifies to their ductility. Thermodynamic analysis shows good thermal properties. Their thermoelectric performances are promising, especially in the spin-down state over the entire temperature range, offering potential applications in applications such as thermocouples and electricity generation from waste heat. Finally, their optical properties suggest possible uses as UV light emitters for high-power light-emitting diodes (LEDs) and as UV filters for protection against harmful UV radiation.