First-principles calculations to investigate magnetic, electronic, and thermoelectric response of europium-based half metallic ternary Zintl compounds EuMg2X2 (X=Sb and Bi)

New materials for spin-polarized charge storage devices are crucial to develop, particularly novel magnetic materials with 100 % spin polarization at room temperature. Numerous compounds in the Zintl family possess this behavior, which is essential to investigate. This study explores the structural, electronic, magnetic, and thermoelectric properties of europium-based new ternary Zintl compounds EuMg2x2 (X = Sb and Bi). The investigation employed the Full-Potential Linearized Augmented Plane Wave + Local Orbitals (FPLAPW + LO) method with GGA (Generalized Gradient Approximation) and GGA + U exchange-correlation potentials within density functional theory (DFT). These properties of EuMg2X2 (X = Sb and Bi) compounds were analyzed for the first time in the Zintl phase of trigonal structure with space group P-3m1 (No. 164). The optimization of structural parameters reveals that EuMg2Bi2 and EuMg2Sb2 Zintl compounds have the lowest ground state energy in the antiferromagnetic (AFM) and ferromagnetic (FM) phases. The calculated structural parameters are in excellent agreement with experimental data. Electronic band profiles and density of states predict the halfmetallic nature of EuMg2Sb2 and EuMg2Bi2. Furthermore, the bonding mainly occurs by hybridizing p-d and d-d states in both compounds. The density of states and magnetic moments indicate AFM in EuMg2Bi2 and FM in EuMg2Sb2. Finally, thermoelectric properties indicate that EuMg2Sb2 displayed the highest achievable Seebeck coefficient of 1.5 x10- 3 mu V/K, while EuMg2Bi2 showed a value of 1.3 x10- 3 mu V/K in the spin-down mode. The calculated figure of merit values indicates that these compounds are suitable for thermoelectric applications. Half metallic nature and AFM/FM of EuMg2Bi2 and EuMg2Sb2, respectively, predict the importance of these compounds in spintronic.