Ferromagnetism and correlated insulating states in monolayer Mo33Te56

Although the kagome model is fundamentally two-dimensional, the essential kagome physics, i.e ., the kagome-bands-driven emergent electronic states, has yet to be explored in the monolayer limit. Here, we present the experimental realization of kagome physics in monolayer Mo ₃₃ Te ₅₆ , showcasing both ferromagnetic ordering and a correlated insulating state with an energy gap of up to 15 meV. This finding is facilitated by an unprecedented structural phase of monolayer Mo-Te compound, which forms a mirror-twin boundary loop superlattice exhibiting kagome geometry and multiple sets of kagome bands, as elucidated by scanning tunnelling microscopy (STM) and theoretical calculations. The partial occupancy of these nearly flat bands results in Fermi surface instability, counteracted by the emergence of ferromagnetic order (with a coercive field ~0.1 T, as observed by spin-polarized STM) and the opening of a correlated hard gap. Our work establishes a robust framework featuring well-defined atomic and band structures, alongside the intrinsic two-dimensional nature, essential for the rigorous examination of kagome physics.