Study of half-metallic ferromagnet RhHfVGa for spintronic and thermoelectric applications

This study presents a comprehensive first-principles investigation of the newly proposed quaternary Heusler compound RhHfVGa, focusing on its structural, electronic, magnetic, thermodynamic, and thermoelectric properties. Density functional theory (DFT) with GGA-PBE96, supplemented by GGA + U and the modified Becke-Johnson potential (mBJ), was employed to ensure accurate band gap characterization. This compound crystallizes in the Type 1 structure, with the optimized lattice constant of 6.354 Å. RhHfVGa exhibits half-metallic ferromagnet (HMF) behavior, with a 100% spin-polarization and a total magnetic moment of 3.00 µB, consistent with the Slater-Pauling rule (M_tot = Z_tot - 18). The results suggest that RhHfVGa is well-suited for spintronic applications. Thermodynamic parameters were successfully calculated, which enhances the credibility of the findings. The heat capacity (Cv = 99.68 Jmol^{- 1}K^{- 1}) approaches the Dulong-Petit limit, a phenomenon common to all solids. The narrow band gaps (approximately 0.98 to 1.26 eV), high n-type electrical conductivities (3.35 × 10¹⁹ (Ω.m.s)^-1 in GGA + U and 8.43 × 10¹⁹ (Ω m s)^-1 in mBJ), and a dimensionless figure of merit (ZT) ranging from 0.82 to 1.65 across various temperatures indicate strong potential for thermoelectric applications.