Investigations of physical properties of some ir-based full heusler alloys within the density functional theory

In this thesis, the structural, electronic, mechanical and thermodynamic properties of Ir2XIn (X = Sc, Ti and V) full Heusler alloys were investigated within the scope of Density Functional Theory (DFT) based on first-principles calculations. The calculations were carried out with the Perdew–Burke–Ernzerhof (PBE) exchange-correlation functional within the Generalized Gradient Approximation (GGA) framework using the Quantum ESPRESSO software package. The alloys were optimized for the L21 type face-centered cubic structure belonging to the Fm-3m space group. The lattice constants obtained were found to be 6.468 Å for Ir2ScIn, 6.376 Å for Ir2TiIn and 6.328 Å for Ir2VIn, respectively. It was determined that the elastic constants (C11, C12, C44) met the mechanical stability conditions and that the alloys were ductile. Electronic band structure and density of states (DOS) analyses indicate that the alloys exhibit semi-metallic behavior. The energy difference in the spin-up and spin-down channels is consistent with the high spin polarization and the total magnetic moment of around 1.00 μB. Thermodynamic calculations indicate that the Debye temperatures are approximately 240 K. Temperature-dependent changes in heat capacity, free energy, and entropy values reveal that the alloys are thermodynamically stable. Consequently, Ir2ScIn, Ir2TiIn, and Ir2VIn alloys are all mechanically stable, semi-metallic, and highly spin polarized compounds. These findings suggest that Ir2ScIn, in particular, is a promising candidate for spintronic and electronic device applications. Keywords: Density Functional Theory (DFT), Electronic and Thermodynamic Properties, Inverse Heusler Alloy.