Cr2Se3: a non-van der Waals platform for designing tunable 2D magnetic materials

초록

The design of magnetic materials is often enabled by rigid crystal frameworks that permit site-selective chemical control without compromising structural integrity, as exemplified by Heusler alloys. Extending this framework-driven design paradigm to low-dimensional systems remains challenging due to the limited structural complexity of many van der Waals (vdW) magnets. Here, using first-principles density functional theory, we establish rhombohedral <bold>Cr2X3</bold> (X = S, Se, Te) as a connectivity-encoded inorganic platform for designing non-van der Waals magnetic materials. Focusing on site-selectively substituted Cr3TMSe6 (TM = V, Mn, W), we show that the mixed face-sharing and edge-sharing Cr-Se octahedral framework remains thermodynamically accessible and dynamically, thermally, and kinetically robust upon substitution. While the Cr-Se network continues to dominate the electronic structure, transition-metal substitution acts as a controlled perturbation that systematically reshapes magnetic ground states, exchange networks, and magnetic anisotropy through distinct orbital and spin-orbit coupling mechanisms. These results demonstrate how framework topology and site chemistry cooperatively govern magnetism in non-van der Waals layered systems, establishing Cr2Se3 as a generalizable platform for materials-by-design beyond conventional 2D magnets.

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