A DFT study of the physical properties of novel vanadium-based half-Heusler alloys VYAl (Y = Ni,Pd, and Pt) pertinent to their optoelectronics application

Abstract

We investigated three novel 18-valence electron count (VEC) vanadium-based half-Heusler alloys, VYAl (Y = Ni, Pd, and Pt), for their structural, mechanical, electronic, and optical properties using density functional theory (DFT). The computation was carried out employing Vienna Ab-initio Simulation Package (VASP) and all three alloys have exhibited structural, chemical, mechanical, and thermodynamic stability. We obtained the lattice constants of 5.520, 5.800, and 5.820 Å for VNiAl, VPdAl, and VPtAl, respectively. The elastic parameters imply a ductile and hard nature of the system and exhibit anisotropic behavior. Electronic band characterization demonstrated that all three alloys are semiconductors with direct narrow gaps at the Γ-point which is crucial for photovoltaic applications. In addition to that, the high density of the band states near the Fermi level indicates a promising candidate for thermoelectric conversion. The influence of SOC interaction in the system generates a small shift in the bands. From the optical response, we infer that the studied compounds have exceptional light absorption and reflection quality, making them suitable for optoelectronics purposes.