Exploring the Thermoelectric, Phonon, and Spin‐Optical Performance of RhVBi Half‐Heusler Compound: A First‐Principles Approach via DFT

ABSTRACT In this work, we present a comprehensive first‐principles investigation of the structural, electronic, magnetic, thermoelectric, phonon, thermodynamic, and spin‐resolved optical properties of the half‐Heusler compound RhVBi using GGA, GGA+U, and modified Becke–Johnson (mBJ) exchange‐correlation schemes. The optimized structure stabilizes in the cubic half‐Heusler phase (space group F‐43m) with a lattice parameter of 11.751 Bohr (6.219 Å). Electronic structure calculations reveal a half‐metallic ferromagnetic ground state characterized by a metallic spin‐up channel and a semiconducting spin‐down channel. The calculated total magnetic moment is approximately 1 μB per formula unit. The absence of imaginary phonon frequencies confirms the dynamical stability of RhVBi. Thermoelectric calculations predict a large Seebeck coefficient (1.45 × 10 − 3 V K − 1 ) and an estimated electronic figure of merit approaching unity (ZT ≈ 1.0) at low temperatures within the constant relaxation time approximation. The optical response exhibits strong photon absorption and a high refractive index, indicating potential for optoelectronic applications. Furthermore, thermodynamic properties obtained from the quasi‐harmonic Debye model reveal a decrease in bulk modulus and Debye temperature with increasing temperature, while heat capacity, entropy, and thermal expansion coefficient increase. These results highlight RhVBi as a promising multifunctional material for spintronic, thermoelectric, and optoelectronic applications.