A deep dive into cation-modified structural, mechanical, magneto‑electronic, and thermophysical properties of MAlO3 (M = Ca, Sr, Ba, and Ra): First-principles investigation

• Phonon dispersion spectra confirm dynamic stability of all MAlO₃ (M = Ca, Sr, Ba, Ra) perovskites. • Dynamic stability is verified across a wide range of external stress conditions. • SrAlO₃, BaAlO₃, and RaAlO₃ exhibit stable ferromagnetic phases, unlike CaAlO₃, which shows a non-magnetic ground state. • CaAlO₃ transitions from metallic to half-metallic under tensile stress exceeding 4%. • Mechanical analysis indicates the ductile nature of the materials. This article presents a first-principles investigation of structural, mechanical, thermophysical, and magneto-electronic properties of MAlO 3 (M = Ca, Sr, Ba, and Ra) perovskites, which have not yet been synthesized experimentally. The ground state energies derived from structural optimizations imply that SrAlO 3 , BaAlO 3 , and RaAlO 3 have stable ferromagnetic phases as opposed to non-magnetic phases like CaAlO 3 . The structural stability of the perovskite candidates under investigation is confirmed by the combined assessment of the tolerance factor and enthalpy of formation energy. Since no soft modes or imaginary frequencies are seen, the phonon dispersion spectra ensure the dynamic stability of the compounds with and without external stress. The spin-polarized electronic properties are calculated using Generalized Gradient Approximation (GGA) and Trans-Blaha modified Becke-Johnson (TB-mBJ) approaches. The electronic and magnetic characteristics of CaAlO 3 reveal metallic features for both up-spin and down-spin channels. In contrast, SrAlO 3 , BaAlO 3 , and RaAlO 3 have half-metallic characteristics displaying a metallic nature in the down-spin channel while acting as insulators in the up-spin channel. However, half-metallic properties are preserved within -6% to +8% of the applied strain for the compounds SrAlO 3 , BaAlO 3 , and RaAlO 3 . Under compressive stress, CaAlO 3 retains its metallic characteristics; however, when tensile strain is above 4%, the material loses these characteristics and becomes half-metallic. The mechanical characteristics demonstrate the ductility of the perovskites. Lastly, theoretical simulations of the thermodynamic and thermoelectric properties are included in this research. We may conclude that the calculated parameters of these half-metallic candidates pave the way for potential use in spintronic and thermoelectric devices.