Physical Science International Journal

In this study, the electronic architecture and magnetic phenomena of iron-doped molybdenum diselenide (MoSe2) monolayers are systematically investigated using first-principles density functional theory (DFT). Employing the Quantum ESPRESSO computational package with GGA-PBE functionals and projector augmented-wave (PAW) pseudopotentials, structural and electronic simulations were performed on a 4 × 4 × 1 supercell featuring a substitutional Fe doping concentration of 12.5%. While pristine MoSe₂ is inherently a non-magnetic semiconductor, our spin-polarised calculations reveal that the introduction of transition-metal impurities induces a robust half-metallic ferromagnetic ground state. Specifically, the majority-spin channel exhibits strong metallic conduction, while the minority-spin channel maintains a distinct forbidden energy gap of 0.651 eV, yielding 100% spin polarisation at the Fermi level. This transition is fundamentally driven by localised exchange interactions and strong orbital hybridisation between the Fe 3d and host Se 4p states. The substituted lattice achieves a macroscopic total magnetic moment of 4.32 \(\mu\)B per supercell, confirming the establishment of a stable ferromagnetic network. Furthermore, mapping the calculated exchange energy (62.92 meV) onto the classical Heisenberg spin model yields a mean-field estimate of the Curie temperature of approximately 487 K. By coupling above-room-temperature thermal stability with half-metallicity, this investigation highlights the potential of Fe-doped 2D MoSe2 for integration into next-generation nanoscale spintronic applications and advanced magnetic memory architectures.