Strain-Resilient 2D Fe ₂ SbS Metallic Antiferromagnet with Intrinsic Dimerization and Tunable above-Room Néel Temperature

The discovery of two-dimensional (2D) materials with robust antiferromagnetism above room temperature is critical for advancing nanoscale spintronic technologies. Using swarm-intelligence structural prediction combined with first-principles calculations, we identify a stable orthorhombic Fe2SbS monolayer with intrinsic bond dimerization. This structural distortion creates two nonequivalent Fe coordination environments, modulating the crystal-field splitting and strain-dependent magnetic anisotropy. The Fe2SbS monolayer exhibits metallic conductivity, a high Néel temperature of 416 K, and a sizable magnetic anisotropy energy of 210 μeV per atom. Its antiferromagnetic ground state originates from the cooperative effects of direct and superexchange interactions. Under biaxial strains from −5% to +5%, the material maintains its antiferromagnetic metallic character, demonstrating strain-resilient antiferromagnetism. These results highlight Fe2SbS as a promising 2D platform for strain-tunable, room-temperature spintronic applications.