Abstract
<title>Abstract</title> <p>First-principles computations were employed to investigate the properties of HfIrX (X = As, Bi). After optimization of the structure, equilibrium lattice parameters are estimated for both HfIrAs and HfIrBi, which equal 6.1379 Å and 6.4637 Å, respectively. Hence, the materials crystallize in the stable half-Heusler structure (F-43m). Examination of the elastic properties confirms that HfIrX compounds have positive elastic constants satisfying the Born criterion. The obtained values of bulk modulus for HfIrAs and HfIrBi are estimated to be 164 GPa and 139.4 GPa, respectively. Moreover, a value above 1.75 for Pugh's ratio and positive Cauchy pressure are consistent with the ductility of both compounds with slightly softened mechanical properties when changing As to Bi. According to our analysis utilizing DFT-GGA, both compounds are identified as semimetals having the Fermi level within the band structure, which implies that the valence band touches the conduction one. Therefore, the semi metallic character is expected to find potential practical applications of these materials in electronics, photonics, spintronics, and thermoelectric. In addition to the results mentioned above, in future work, we plan to include the Hubbard U parameter for the d-electrons of Ir atoms to account for on-site Coulomb repulsion.</p>