Spin Transport Characteristics of Equiatomic Quaternary Heusler Alloys for High Temperature Thermoelectrics

We investigated novel Na‐based equiatomic quaternary Heusler alloys (EQHAs) by means of density functional theory for high‐temperature thermoelectrics. The mechanical, structural, electronic, thermodynamic, magnetic, and thermoelectric transport‐related physical parameters were calculated. As part of our theoretical investigation, we computed the ground state characteristics for a wide range of potential structural and magnetic configurations. Our calculations showed that both NaCoVSb and NaCoVSn have a negative formation energy, which is an indication of their phase stability. Mechanical characteristics like shear, bulk, and Young's moduli, as well as Poisson's and Pugh's ratios, were obtained by computing elastic constants. Our calculation shows that NaCoVSn displays half‐metallic behavior in the minority spin channel with a bandgap of 0.47 eV. We use the mean field method and find that the Curie temperature is above 300 K. Our calculations also show that NaCoVSb and NaCoVSn had thermoelectric efficiencies (ZT) of 1.01 (300 K) and 1.18 (300 K), respectively. Our examination of other temperature and pressure‐related thermodynamic properties verified the stability of these alloys.