DFT study of structural, elastic, electronic, magnetic, thermal and transport properties of new multifunctional NiVSn half-Heusler for spintronic and thermoelectric applications

In this work, the first-principles density functional calculations of the structural, elastic, electronic, magnetic, thermal and thermoelectric properties of NiVSn half-Heusler compound are carried out. The exchange and correlation potential are treated by using Generalized Gradient approximation of Perdew, Burke and Ernzerhof (GGA-PBE), GGA plus Tran-Blaha-modified Becke-Johnson (mBJ-GGA) approach and mBJ-GGA+U where U is the Hubbard on-site Coulomb interaction correction (mBJ-GGA+U). Structural calculations revealed that NiVSn is stable in type 1 structure ferromagnetic state. Elastic properties show that our compound is mechanically stable, ductile and anisotropic. The results of the band structures and density of states display a half metallic behavior of NiVSn with an indirect bandgap of 0.476, 0.508 and 0.845 eV by using GGA-PBE, mBJ-GGA, and mBJ-GGA+U, respectively. The total magnetic moment calculated is integer of 1 mu B confirming a half metallic behavior of NiVSn and follows the well-known Slater-Pauling rule (mu(tot) = Z(tot) - 18); therefore, the studied compound is suitable for application in spintronic fields. The thermodynamic properties such as bulk modulus, the heat capacity, the Debye temperature, and the thermal expansion coefficient are investigated using quasi-harmonic Debye model (QHDM). The thermal results show that NiVSn can be applied in extreme temperature and pressure conditions. The thermoelectric properties are studied employing the BoltzTrap code. The calculated transport properties are very interesting for the spin-down channel with high electrical conductivity, high Seebeck coefficient, and figure of merit value approaching unity. As a result, the half-Heusler alloy NiVSn is a promoter for conventional thermoelectric materials.