Electronic structure, mechanical, phonon, magnetic, and transport analysis of newly inorganic halide double perovskite semiconductors Rb₂GeMnX₆ (X = Cl, Br) from first-principles DFT calculations

For the first time, in this computational aspect, we have reported the various intrinsic physical properties of newly inorganic halide double perovskite semiconductors Rb₂GeMnX₆ (X = Cl, Br) upon the basis of full potential linearized augmented plane wave (FP-LAPW) integrated in Wien2k package. Primarily, the attempt was made to define the structural stability of both these perovskite structures by evaluating their total ground state energies, via from the Brich Murnaghan equation of state, which addresses the possible ground state energy in ferromagnetic (FM) rather than competing anti-ferromagnetic (AFM) phases. Meanwhile, the retrieved optimized lattice constants are in rational accord with benchmark studies reported by others. Later on, the electronic structures of these alloys has been executed by the calibration of certain functional schemes viz; Perdew-Burke Ernzerhof-Generalized Gradient Approximation (PBE-GGA) in conjunction with the Hubbard model (GGA + U) and along with the Tran-Blaha modified Becke-Johnson (TB-mBJ), which portrays the existence of semiconducting nature via seen from their corresponding band structures as well as density of states. More likely, the spin-splitting from their two-dimensional band structures discloses a net magnetism of 5µ_B within each alloy, specifies their facial route for spintronic applications. Subsequently, the mechanical stability by enumerating the three distinct elastic constants due to their cubic symmetry has been computed via Cubic Elastic Package. With the help of density functional perturbation theory (DFPT), the context of phonon stability has been studied. In addition, semi-classical Boltzmann theory integrated within the sophisticated BoltzTraP package has been properly applied to forecast various transport results. Being displaying the necessary stability conditions and also the various promising features lends their way towards the cutting-edge applications in spintronics and sustainable green energy harvesting technologies.