Computational Evaluation of Pressure Effects on Cubic Ferromagnetic Perovskites ACrBr3(K, Rb, Cs, Fr): Materials Engineering Perspectives for Spintronics and Optoelectronics Via DFT

Abstract

In this study, the pressure-dependent properties of cubic ferromagnetic metal halide single perovskites ACrBr_3 (K,Rb,Cs,Fr) were systematically investigated using density functional theory (DFT). The tolerance factor and octahedral factor indicate that the investigated compounds are stable in a cubic structure having Pm3 @#x0305;m(221) space group. Structural analysis shows that both unit cell volume and lattice constants decrease with increasing external hydrostatic pressure range 0-30GPa. Mechanical stability is confirmed through Born stability criteria and pressure enhances the elastic constants, further supporting their robustness for device integration. Spin-polarized band structure and density of states (DOS) analysis confirm the half-metallicity, where the spin-up state is metallic and the spin-down state is either an indirect band gap. Our studied materials have 100% spin polarization at the Fermi level. Pressure decreases the band gap for all of our investigated materials. The total magnetic moment in all compounds remains approximately an integer value, confirming their suitability for spintronic applications. Thermodynamic parameters, including Debye temperature and melting temperature, exhibit an upward trend with increasing pressure, indicating enhanced stability and potential for thermoelectric applications. Although the Curie temperature decreases under applied pressure, it remains significantly above room temperature, ensuring the persistence of ferromagnetic ordering under practical operating conditions. Optical properties such as dielectric constants, conductivity, absorption coefficient, reflectivity, refractive index and loss functions of our studied materials show the highest intensity in the UV region and increase with the applied pressures. These findings highlight the multifunctional potential of ACrBr_3 (K,Rb,Cs,Fr) perovskites in next-generation spintronic and optoelectronic devices as well as in thermoelectric engineering applications.