First-principles calculations to investigate structural, mechanical, electronic, magnetic and thermoelectric properties of Tl ₂ WX ₆ (X=Cl, Br and I), tungsten-based variant perovskite

In this paper, we report the structural, elastic, electromagnetic, thermodynamic and thermoelectric properties of half-metallic variant perovskite compounds Tl 2 WX 6 (X[Formula: see text]Cl, Br and I). These properties were calculated by executing the full potential linearized augmented-plane-wave method for solving the Kohn–Sham equation of Density Functional Theory. The ferromagnetic nature of these compounds was confirmed in the volume optimization process. These compounds showed stability and demonstrated appropriate tolerance factors. The tolerance factors of Tl 2 WCl 6 , Tl 2 WBr 6 and Tl 2 WI 6 were found to be 1.008, 0.98 and 0.96, respectively. These compounds also confirmed stability by exhibiting negative formation energies which were calculated as [Formula: see text]2.69[Formula: see text]eV, [Formula: see text]2.09[Formula: see text]eV and [Formula: see text]1.24[Formula: see text]eV, respectively, for Tl 2 WCl 6 , Tl 2 WBr 6 and Tl 2 WI 6 . To determine the precise electronic nature and magnetic moments, the GGA[Formula: see text]U potential was employed. For each compound, the total spin magnetic moment was 2.00[Formula: see text] [Formula: see text]B per formula unit. These perovskites revealed a half-metallic nature, behaving as metals in the spin-up channel while acting as semiconductors in the spin-down channel. The elastic parameters were calculated using the elastic code embedded in Wien2k. Finally, spin and temperature-dependent thermoelectric parameters such as electronic thermal conductivity, lattice thermal conductivity, Seebeck coefficient, conductance and figure of merit were calculated by implementing the BoltzTrap code.