Computational dissection of single-layer intrinsic ferromagnetic semiconductor Mn₂AX₆(A=Al, Ga; X=Cl, Br, I) with...

Two-dimensional intrinsic ferromagnetic semiconductors (IFMS) have emerged as a pivotal research frontier in spintronics, uniquely enabling integration of semiconductor electronics with non-volatile magnetic storage at finite temperatures. Using first-principles calculations, we systematically investigated the structural stability, electronic, and magnetic properties of potential Mn₂AX₆(A=Al, Ga; X=Cl, Br, I) materials with large-moment IFMS characteristics. Results confirm that these stable materials are indeed IFMS with an indirect bandgap ranging from 0.5 to 1.3 eV and a magnetization of 9μB u.c.^-1And their IFMS characteristics show exceptional resilience to strain. The semiconducting property transition to half-metal characteristic only when compressive strain exceeds 7% (as seen in Mn₂AlCl₆), while spin-polarized band inversion occurs when the strain shifts from compressive to tensile. Additionally, these monolayers consistently exhibit out-of-plane easy magnetization axes with magnetic anisotropy energy of 0.028-2.1 meV and Curie temperatures (T_c) of 164-303 K. Further studies on magnetic mechanism reveal that their ferromagnetic ground states are predominantly governed byd_xy-p_xy-d_xysuperexchange interactions within Mn-X-Mn pathways near ∼90°, with the concomitant high-T_cbeing attributable to the larger magnetic moments (∼4.6μ_B) of Mn²⁺and strong second- and third-nearest- neighbor Mn-Mn magnetic interactions compared to other transition metal (TM) dihalides. Collectively, these IFMS materials Mn₂AX₆, with advantages including strain-tunable spin flip and balanced magnetic properties, may exhibit greater potential than other TM halides for magnetic storage and magnetic sensor applications.