Insulating charge transfer ferromagnetism in moiré superlattices

The transition metal dichalcogenide (TMD) moiré system has recently emerged as a platform for realizing Hubbard physics, promising to capture the interplay among strong electron correlations, magnetism, and band topology. In a honeycomb lattice with a vertical electrostatic gating field that breaks the particle-hole symmetry, we identify a mechanism for ferromagnetism at integer filling factors without Hund's coupling. Using ED, DMRG calculations, and perturbation theory, we show that ferromagnetism occurs in a critical charge-transfer regime and remains stable in the presence of complex hopping amplitudes and slight doping. Our theory explains the experimentally observed ferromagnetism in twisted bilayer MoTe₂ near filling factor ν_h=1 under intermediate gate fields.