Structural, electronic, and magnetic properties of Mn₂Co_1-xV_xZ (Z = Ga, Al, x = 0, 0.25, 0.5, 0.75, 1) Heusler alloys were theoretically investigated for the case of L2₁ (space group Fm$\overline{3}$m), L2_1b (L2₁ structure with partial disordering between Co and Mn atoms) and XA (space group F$\overline{4}$3m) structures. It was found that the XA structure is more stable at low V concentrations, while the L2₁ structure is energetically favorable at high V concentrations. A transition from L2₁ to XA ordering occurs near x = 0.5, which qualitatively agrees with the experimental results. Comparison of the energies of the L2_1b and XA structures leads to the fact that the phase transition between these structures occurs at x = 0.25, which is in excellent agreement with the experimental data. The lattice parameters linearly change as x grows. For the L2₁ structure, a slight decrease in the lattice constant a was observed, while for the XA structure, an increase in a was found. The experimentally observed nonlinear behavior of the lattice parameters with a change in the V content is most likely a manifestation of the presence of a mixture of phases. Almost complete compensation of the magnetic moment was achieved for the Mn₂Co_1-xV_xZ alloy (Z = Ga, Al) at x = 0.5 for XA ordering. In the case of the L2₁ ordering, it is necessary to consider a partial disorder of atoms in the Mn and Co sublattices in order to achieve compensation of the magnetic moment.

First-principles calculations of the stability, electronic, and magnetic properties of full-Heusler compound V₂FeSi and Fe₂VSi in regular ($L{2}_1$) and inverse ($XA$) structures have been performed using density functional theory within an SCAN meta-GGA functional. It is found that the $XA$ crystal lattice is energetically more favorable for V₂FeSi, while Fe₂VSi forms the $L{2}_1$ structure. In both cases, the electronic structure of the energetically stable modifications corresponds to half-metallic ferrimagnets. Magnetic properties of energetically favorable structures obey the Slater–Pauling rule. All considered properties of the studied structures are explained within the crystal orbital Hamilton population analysis.

This research investigates the structural, electronic, mechanical, and vibrational properties of double half-Heusler compounds with the generic formula Ti2Pt2ZSb (Z = Al, Ga, and In) using density functional theory calculations. The generalized gradient approximation within the Perdew-Burke-Ernzerhof functional was employed for structural optimization and the hybrid HSE06 functional for electronic properties. Our results demonstrate that these compounds are energetically favorable, dynamically and mechanically stable. Electronic structure calculations reveal that Ti2Pt2AlSb double half-Heusler compound is a non-magnetic semiconductor with an indirect bandgap of 1.49 eV, while Ti2Pt2GaSb and Ti2Pt2InSb are non-magnetic semiconductors with direct bandgaps of 1.40 eV. The alloys exhibit low lattice thermal conductivity (2.35–2.66 W/mK) and high melting temperature (1211–1248 K), making them promising candidates for high-technological applications. Further performed analysis, including phonon dispersion curves, electron localization function (ELF), and Bader charge analysis, provides insights into the bonding character and vibrational properties of these materials.

In this study, a systematic investigation of the structural, electronic, and mechanical properties of CuNiZ (Z = Al, Ga, Sb, Sn) half-Heusler alloys was carried out based on density functional theory (DFT). The obtained results confirm the dynamical and mechanical stability of these alloys and provide insights into their structural symmetry and bonding nature. The electronic structure analysis revealed that CuNiZ alloys exhibit metallic behavior, while the calculated elastic moduli and Poisson's ratio characterize their mechanical strength. Furthermore, the calculations indicated the dominance of ionic bonding in these alloys and confirmed their compliance with fundamental mechanical stability criteria. The CuNiAl, CuNiSb, and CuNiSn alloys were found to be mechanically stable, with their anisotropy coefficients and other elastic parameters determined. This study demonstrates that CuNiZ half-Heusler alloys are promising candidates for functional materials. In particular, their mechanical robustness and structural properties make them potential candidates for applications in thermoelectric and spintronic devices.