Investigating the electronic structure, elastic, magnetic, and thermoelectric nature of NiVXSc1-XSb quaternary half-Heusler alloys

Abstract

The structural, electronic, magnetic, elastic, and thermoelectric properties of NiVxSc1-xSb half Heusler alloys with different compositions were investigated employing a self-consistent first-principles-based calculation that uses the full-potential linearized-augmented-plane-wave method. The structural characteristics, such as the bulk modulus and lattice constants, are examined with various vanadium concentrations. The accurately modified Becke Johnson potential was used to calculate the band gap energies. The equilibrium lattice parameter of NiScSb type-I structure has the lowest energy and seems to be most stable among the other configurations with a lattice constant value of 6.04 Å, which deviates from the experimental results by up to 0.5%. The bulk modulus rises as the lattice constant decreases. The ground states of the studied alloy structures are dynamically stable, as concluded by the non-existence of negative phonon frequency. The band structure of NiScSb (for x = 0) was predicted as a non-magnetic semiconductor with an indirect band nature, and an energy gap value of 0.244 eV along (Γ-point > X). This tendency was further supported by the symmetrical shape of the curves that reflect the densities of states for these configuration channels. The thermoelectric characteristics of these various combinations were also thoroughly investigated and discussed.