Prediction of the structural, elastic, electronic, and thermoelectric properties of quaternary Heusler compounds TaSiFeMn, TaAlCuCo, and SrBaZnSi

In this study, we conducted a detailed investigation of the structural, elastic, electronic, and thermoelectric properties of the quaternary Heusler compounds TaSiFeMn, TaAlCuCo, and SrBaZnSi. The calculations were performed using the full-potential linearized augmented plane waves (FP-LAPW) method within the framework of the density functional theory (DFT), as implemented in the WIEN2k code. The generalized gradient approximation (GGA-WC) was employed for the analysis of structural and elastic properties, while the Tran–Blaha modified Becke–Johnson (TB-mBJ) potential, within the GGA-WC scheme, was applied to evaluate the electronic and thermoelectric properties. The results reveal that the these materials exhibit exclusively a non-magnetic phase. Employing GGA-WC and TB-mBJ potential, the electronic investigation show that TaSiFeMn and TaAlCuCo are semiconductors with indirect band-gap of 0.421 eV and 0.167 eV respectively, while SrBaZnSi behaves as a metal. Moreover, our analysis indicates that TaSiFeMn, TaAlCuCo, and SrBaZnSi are mechanically stable with a net ductility of TaSiFeMn and TaAlCuCo compared to SrBaZnSi. In particular, TaAlCuCo displays more pronounced anisotropy than the other materials. The bulk modulus values derived from elastic constants show excellent agreement with those obtained from structural properties, thereby confirming the robustness and reliability of this study. Finally, transport properties provide a figure of merit ZT = 0.95 and 0.85 for TaSiFeMn and TaAlCuCo respectively beside a relatively high Power factor around 10 12 W/mK 2 s suggesting their potential application in thermoelectric devices.