Exploring quaternary Heusler alloys RhX'ZrZ (X' = Cr, fe; Z = Si, Ge) for advanced spintronic devices: A first-principles approach

We have conducted a detailed ab initio study of the half-metallic quaternary Heusler alloys RhX'ZrZ (X' = Cr, Fe; Z = Si, Ge), where RhCrZrSi and RhFeZrSi exhibit near-perfect spin-polarization with half-metallic gaps of 0.49 eV and 0.51 eV, respectively. They retain half-metallicity over wide range of lattice showing further stability under tetragonal strain within wide ranges of the c/a ratio (RhCrZrSi: - 2%-2 %, RhFeZrSi: -8.4 %-9.6 %). While, RhCrZrGe and RhFeZrGe demonstrate near half-metallicity that turn to act as perfect half-metal under specific strain. All materials display Curie temperatures (TC) above room temperature, with RhFeZrSi achieving 1376 K. These alloys are thermodynamically, mechanically, and dynamically stable, with RhFeZrSi exhibiting maximum stiffness and RhCrZrSi demonstrating superior hardness due to high bulk and shear moduli. Their integer magnetic moments follow the Slater-Pauling rule (ZT = MT - 24), confirming their potential for spintronics. This study highlights their potential for next-generation spintronic devices.