Structural stability, electronic and magnetic properties of a new quaternary Heusler magnetic semiconductor material: first-principal study

Heusler compounds, known for their diverse physical properties and applications, have garnered considerable interest. In this study, we investigate the mechanical, dynamic, and thermodynamic phase stability, along with the electronic and magnetic characteristics of the CoMnTaSb quaternary Heusler alloy, utilizing density functional theory (DFT) calculations. The full-potential linearized augmented plane wave (FP-LAPW) approach is employed. Exchange–correlation effects are treated using the generalized gradient approximation (GGA) and the modified Becke–Johnson potential (GGA + mBJ). Phonon dispersion frequencies, cohesive and formation energies, convex hull distance, and elastic constants all confirm the stability of the CoMnTaSb compound, supporting its feasibility for experimental synthesis. It has been determined that the CoMnTaSb compound is apt for room-temperature applications due to its high Curie temperature. Within the GGA (GGA + mBJ) approximation, our calculations predict that the compound exhibits magnetic semiconducting behavior, with band gaps of 0.196 (0.470) eV along the L–X direction in the spin-up state and 0.189 (0.441) eV along the Γ–X direction in the spin-down state. An integer total magnetic moment of 2.00 μ_B per formula unit is found, satisfying the Slater–Pauling rule \({m}_{\text{tot}}=\left(Z-24\right) \,{\mu }_{B}\). The electronic and magnetic properties of the CoMnTaSb quaternary Heusler compound under hydrostatic pressure are also analyzed.