Two-Dimensional Room-Temperature Magnetism in Janus Mn₂I₃S₃ and Cr₂I₃Se₃ Monolayers with Tunable Magnetic Properties...

Exploring room-temperature intrinsic magnetism in two-dimensional (2D) materials for nanoscale spintronic devices has garnered significant interest. Achieving a high Curie temperature and substantial spin polarization in 2D ferromagnetic materials remains challenging. Drawing inspiration from the substantial enhancement of the Curie temperature observed in ferromagnetic CrIS monolayers by manipulating the covalent nature of Cr-S bonds, our study systematically delves into the electronic structure and magnetic properties of Janus M₂X₃Y₃ (M = V, Cr, Mn, Fe, and Co; X = Cl, Br, I; Y = S, Se, and Te) monolayers through first-principles calculations. Our findings reveal that 15 kinds of these monolayers exhibit dynamic and thermodynamic stability while displaying diverse electronic and ferromagnetic characteristics. Notably, Mn₂I₃S₃ demonstrates half-metallicity and in-plane magnetic anisotropy, while Cr₂I₃Se₃ exhibits a half-semiconductor and perpendicular magnetic anisotropy. Consequently, Mn₂I₃S₃ transforms from in-plane to perpendicular magnetic anisotropy through strain manipulation. Cr₂I₃Se₃, under strain, transforms from a half-semiconductor to a bipolar magnetic semiconductor. The strong coupling caused by the M-Y bonds makes them have a Curie temperature higher than room temperature. The unique magnetic properties exhibited by the 2D Janus Mn₂I₃S₃ and Cr₂I₃Se₃ magnets hold promise for applications in spintronics. Our study provides a foundational understanding for future experimental explorations in this exciting research area.