Room-temperature half-metallic magnetism in stable self-intercalated 3d transition metal chalcogenide bilayers

The search for 2D magnets with Curie temperatures above room temperature is crucial for spintronics. Intercalation in 2D materials is a promising strategy to improve performance. We performed a thorough density functional theory (DFT) calculation on 2D M(2+σ)X4 (where M = V, Cr, Mn, or Fe; X = S, Se, or Te) magnets, derived from self-intercalated 3d transition metal dichalcogenide MX2 bilayers. The investigations revealed stable 2D magnets, including half-metals and magnetic semiconductors with critical temperatures (TC) above room temperature. Self-intercalation in the van der Waals gap forms molecular orbital states that significantly affect magnetic coupling. The magnetic anisotropy is minimal compared to interlayer couplings, indicating a unique intrinsic magnetism different from the 2D MX2 precursors. These insights should be valuable for the development of spintronic devices.