A study of stable half-metallic variant perovskites X₂TaCl₆ (X = K, Cs) for possible spintronic applications

In this study, we present first-principles calculations of the X₂TaCl₆ (X = K, Cs) compounds, which are cubic, perovskite-related inorganic materials analogous to K₂PtCl₆-type structures. The computations were performed using the full-potential linearized augmented plane wave method implemented in the Wien2k code. Exchange-correlation effects were treated within the generalized gradient approximation, with and without the inclusion of a Hubbard parameter to account for electronic correlations. Dynamical stability was confirmed through positive phonon frequencies. The relative stability of ferromagnetic and antiferromagnetic phases was assessed via volume optimization, revealing ferromagnetic ground states for both compounds. Structural parameters, including lattice constants, bulk modulus, pressure dependence of the bulk modulus, volume, and ground state energies, were computed and compared with available experimental and theoretical data. Electronic structure analysis indicated a half-metallic behavior in both compounds, with each exhibiting a total magnetic moment of 1µ _B. The Curie temperatures, estimated using the random phase approximation, were found to be 583.55 K for K₂TaCl₆ and 612.30 K for Cs₂TaCl₆. These findings suggest that both variants perovskites, X₂TaCl₆ are promising candidates for spintronic applications.