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We provide a thorough study of the structural, elastic, electronic and magnetic properties of the perovskite solid solution of Sr1−xBaxFeO3 within the framework of density functional theory (DFT), using the full-potential linearized augmented planewave plus local orbital FP-(L)APW+lo method. The found results provide predictions for the mixed perovskite solid solution Sr1−xBaxFeO3 (x = 0.25, 0.5, 0.75) for which no experimental or theoretical data are presently available. These compounds were supposed to have a cubic ferromagnetic structure for all xcompositions. The GGA-PBE functional was chosen for the prediction of the structural properties, in particular the lattice parameter, the bulk modulus and its pressure derivative as well as the cohesive energy. For testing the mechanical stability of the Sr1−xBaxFeO3 compounds, we have studied their elastic constants and it has been found that these compounds are mechanically stable in their cubic perovskite structure. Several parameters related to the elastic constants have also been predicted, in particular Young’s modulus, the shear modulus, Poisson’s ratio, the anisotropic factor and the Debye temperature (θD). For the correct treatment of the high correlation of 3d-iron electrons, the Hubbard correction and TB-mBJ potential were added to the GGA-PBE functional for the analysis of the electronic and magnetic properties of Sr1−xBaxFeO3. It has been found that they are half-metals with a total magnetic moment of ∼ 4µB [ABSTRACT FROM AUTHOR]

To compute the structural, electronic, optical, elastic, and thermoelectric (TE) characteristics of Cs 2 ScTlCl 6 and Cs 2 YTlCl 6 halide double perovskites, the first principles method is employed by using density functional theory (DFT) based full potential linearized augmented plane wave (FP-LAPW) scheme. Band structure (BS) and density of states (DOS) revealed the direct band gap (E g) of 4.44/5.22 eV for Cs 2 ScTlCl 6 /Cs 2 YTlCl 6 , correspondingly. To explore the thermodynamic and structural stability of the Cs 2 ScTlCl 6 and Cs 2 YTlCl 6 , the formation enthalpy (ΔH) and tolerance factor (τ) are computed. The optical absorption edges are located at 3.8 for Cs 2 ScTlCl 6 and 5.1 eV for Cs 2 YTlCl 6. The distinct absorption characteristics observed, particularly in the UV spectrum, suggest that both materials hold promise for use in advanced optoelectronic devices. Elastic constants for both compounds are predicted to determine mechanical features. The Poisson's ratio and Cauchy pressure (CP) depicted brittle nature of both perovskites. Furthermore, BoltzTraP program is utilized to examine TE features and the analysis of ZT spectrum reveals an increase in ZT, rising from 0.747 to 0.800 for Cs 2 ScTlCl 6 and from 0.740 to 0.802 for Cs 2 YTlCl 6 , as temperatures increase from 300 to 800 K. TE materials, with enhanced ZT values, hold promise for diverse applications, including efficient power generation, wearable technology, automotive systems, space exploration, and industrial processes. [ABSTRACT FROM AUTHOR]