Exciton mediated interaction between moiré trapped carriers*

Moiré pattern formed by stacking two-dimensional materials can realize superlattice confinement of electrons or holes, which  is a promising platform to study their many-body interactions. Moire superlattices of semiconducting transition metal dichalcogenides also host excitons, the tightly bound electron-hole pairs that can be interconverted with photons. We investigate the Coulomb exchange interaction between excitons and moiré potential trapped carriers, and show that the optically excited excitons can mediate a ferromagnetic spin-spin interaction between the moire trapped carriers. This interaction can be of longer range than that of pure electronic origin in the absence of excitons, and allows optical tuning of the spin-spin interaction and magnetic orders in the moire superlattice.