Coulomb-correlated states of moir\'e excitons and charges in a semiconductor moir\'e lattice

Semiconductor moir\'e heterostructures exhibit rich correlation-induced many-body phenomena with signatures of emergent magnetism, Mott insulating states or generalized Wigner crystals observed in optical spectroscopy by probing intralayer excitons. However, as the staggered band alignment in the underlying WSe$_2$/WS$_2$ heterobilayer system separates photoexcited electrons and holes to form lowest-energy interlayer excitons, direct access to interactions between correlated charge states and ground state moir\'e excitons remained elusive. Here, we use MoSe$_2$/WS$_2$ heterostacks with type-I band alignment to probe Coulomb interactions of elementary charges with the ground and excited states of moir\'e excitons. In addition to positive and negative moir\'e trions reminiscent of their canonical counterparts in monolayer MoSe$_2$, we reveal novel many-body states formed between moir\'e excitons and charges at fractional filling factors of the periodic moir\'e lattice. For both electrons and holes, these states exhibit doping-dependent Land\'e factors as a hallmark of correlation-induced magnetism, identifying the MoSe$_2$/WS$_2$ heterobilayer as a unique system for studies of correlated phenomena in ambipolar doping regimes.