Programmable 2D Magnetic Clusterphenes With High Curie Temperature and Strong Magnetic Anisotropy via Cluster Assembly and Ligand Synergy

ABSTRACT Achieving high Curie temperature ( T _C ) and large magnetic anisotropy energy (MAE) remains a central challenge for 2D magnets, owing to the intrinsic difficulty of concurrently enhancing magnetic exchange interactions and spin–orbit coupling (SOC) in reduced dimensions. Here, we propose a ligand‐mediated cluster‐assembly strategy for designing 2D magnets, in which magnetic clusters with intrinsically delocalized electronic states are directly assembled into extended 2D lattices. Distinct from atom‐ or molecule‐linked frameworks, this approach amplifies electron delocalization across intercluster connections. Using first‐principles density functional theory calculations, we systematically investigate a family of 2D clusterphenes constructed from ligand‐functionalized M ₆ X ₈ clusters (M = Cr, Co, Fe; X = S, Se, Te). We identify Cr‐based M ₆ X ₈ clusterphenes as robust 2D ferromagnets with T _C exceeding room temperature and exceptionally large MAE. These properties originate from cooperative electronic delocalization within and between clusters, as well as symmetry‐breaking lattice architectures that jointly strengthen superexchange interactions and SOC. In contrast, Co‐ and Fe‐based clusterphenes preferentially stabilize antiferromagnetic ground states. Importantly, ligand functionalization provides a chemically programmable handle to modulate electronic delocalization, magnetic exchange, SOC, and magnetic anisotropy, enabling precise control over magnetic properties. Our results establish magnetic cluster self‐assembly as an extensible platform for engineering high‐performance 2D magnets.