Engineering Stable Half‐Metallic RbIrCl ₃ and RbIrBr ₃ Perovskites for Spintronic and Optoelectronic Technologies: Evidence From DFT, Phonon, and AI

ABSTRACT

DFT computations were carried out to examine the structural, electronic, magnetic, elastic, thermodynamic, and optical attributes of the cubic halide perovskites RbIrX ₃ (X = Cl, Br), executing the full‐potential linearized augmented plane wave (FP‐LAPW) method within the generalized gradient approximation (GGA) and modified Becke–Johnson (mBJ) potential. Structural optimization reveals that the ferromagnetic phase is stable in both compounds. Phonon dispersion calculations reveal the complete absence of imaginary frequencies throughout the Brillouin zone, confirming the intrinsic dynamical stability of both perovskites. Furthermore, ab initio molecular dynamics (AIMD) simulations performed at 300 K demonstrate stable temperature, total‐energy, and RMSD profiles over the simulation period, validating their thermal robustness under ambient conditions. The estimated elastic constants meet the Born stability criterion, verifying mechanical stability; however, the evaluated elastic moduli show ductile behavior and elastic anisotropy. Both compounds exhibit ductile behavior, as indicated by their Pugh ratios of 2.70 and 3.34, respectively. The positive Cauchy pressures (16.53 and 18.94 GPa) further support this behavior. Poisson's ratios are 0.33 and 0.36, while anisotropy factors are 0.39 and 0.32 for RbIrCl ₃ and RbIrBr ₃ , respectively, indicating ionic‐type bonding and elastic anisotropy. Half‐metallic ferromagnetism is shown by electronic structure simulations, where the spin‐down channel has band gaps of 1.59 eV for RbIrBr ₃ and 1.88 eV for RbIrCl ₃ , resulting in 100% spin polarization at the Fermi level. The spin‐up channel displays metallic behavior. The Ir‐5d states under octahedral crystal‐field splitting are the primary source of the magnetic moment, which is about 1 μB per formula unit. Strong hybridization between Ir‐5d and halogen‐p orbitals close to the Fermi level is revealed by partial density of states analysis. Stable behavior under changing pressure and temperature circumstances is indicated by thermodynamic characteristics. In the visible and ultraviolet spectrum, optical measurements reveal considerable absorption, optical conductivity, moderate reflectivity, and substantial optical activity. These results demonstrate that RbIrCl ₃ and RbIrBr ₃ are half‐metallic ferromagnets with good spintronic and optoelectronic potential that are mechanically resilient and dynamically stable.