Unravelling electronic, elastic, plasmonic, and thermoelectric transport properties of HfMCu 2 (M = Al, In, Zn) inverse Heusler alloys via first-principles study

The exploration of innovative multifunctional materials for sustainable energy and thermoelectric applications brought about considerable focus on ternary intermetallic compounds because of their tunability as well as durability. In this work, we present a comprehensive first-principles investigation of the structural, electronic, elastic, plasmonic, and thermoelectric transport attributes of the inverse Heusler alloys [Formula: see text] (M[Formula: see text] [Formula: see text] [Formula: see text]Al, In, Zn) using Density Functional Theory (DFT). Structural optimization establishes the energy stability of the inverse Heusler phase, whereas electronic structure analysis indicates a metallic ground state subject to significant p–d orbital hybridization at the Fermi level. The elastic evaluation finds that all three alloys exhibit mechanical stability along with intrinsic ductility, as illustrated by Pugh’s ratios above 1.75. The [Formula: see text] compounds demonstrate significant elastic anisotropy, characterized by a Zener anisotropy factor of 16.44, indicating unique strain-dependent mechanical behaviors. The dielectric functions and electron energy-loss spectra reveal significant bulk plasmon resonances in the Ultraviolet (UV) energy range (10–12[Formula: see text]eV), establishing these materials as potential alternatives for UV plasmonic applications. Additionally, semi-classical Boltzmann transport calculations demonstrate strong electrical conductivity suggestive of metallic properties. Despite the intrinsic Figure of Merit (zT) being small ([Formula: see text]), the presence of pronounced peaks in the transport coefficients suggests that thermoelectric performance can be substantially improved by Fermi level variation. The findings characterize the [Formula: see text] family as versatile multifunctional materials suitable for applications including flexible electronic interconnects, UV-plasmonic applications, and waste heat recovery systems.