Molecule-Induced Huge d-p Overlap Enhances Superexchange Interaction for Room-Temperature In-Plane Magnetism and Giant Magneto Band-Structure Effect in Ferromagnetic Clusterphene

The discovery of 2D van der Waals XY ferromagnets is a vital task to access excellent topological spin textures, yet remains a longstanding challenge due to low critical temperatures (T_C) and weak in-plane magnetic anisotropy. Here, a novel 2D ferromagnetic clusterphene, (Cr₃As₂)₂Cp₃ (Cp = cyclopentadienyl), by using Cr₃As₂Cp₃ cluster self-assembly with Cp as linker is proposed. Via first-principles calculations, it is demonstrated that an enhanced ferromagnetic superexchange interaction between the d orbital is achieved through a salient overlap onto the molecular frontier orbitals of the Cp ligand, producing a room-temperature T_C. The (Cr₃As₂)₂Cp₃ clusterphene characterizes an ideal XY ferromagnet and a giant magneto band-structure (GMB) effect. Functional groups and element modifications are also introduced to effectively manipulate the magnetic anisotropy and the GMB effect. The results showcase that 2D magnetic cluster-assembled clusterphenes fuel a wide range of possibilities for exploring XY magnetism in reduced dimensions.