Emergent magnetism and spin liquids in an extended Hubbard model at fractional filling
Phys. Rev. B 113, 045132 – Published 20 January, 2026
DOI: https://doi.org/10.1103/by2b-wxfq
Abstract
Motivated by twisted transition metal dichalcogenides (TMDs), we study an extended Hubbard model with both onsite and off-site repulsive interactions, in which Mott insulating states with concomitant charge order occur at fractional fillings. To resolve the charge ordering as well as the fate of the local moments formed thereby, we perform large-scale density matrix renormalization group calculations on cylindrical geometries for several filling fractions and ranges of interaction strength. Depending on the precise parameter regime, both antiferromagnetically ordered as well as quantum-disordered states are found, with a particularly prominent example being a quantum spinliquid type ground state on top of charge ordering with effective kagomé geometry. We discuss the different mechanisms at play in stabilizing various electronic and magnetic states. The results suggest that moiré TMDs are a promising venue for emergent quantum magnetism of strongly interacting electrons.
