Optical nonlinearities and spontaneous translational symmetry breaking in driven-dissipative moiré exciton-polaritons

Abstract

Moiré lattices formed from semiconductor bilayers host tightly localized excitons that can simultaneously couple strongly to light and possess large electric dipole moments. This facilitates the realization of new forms of polaritons that are very strongly interacting and that have been predicted to lead to strong optical nonlinearities controlled by multiphoton resonances. Here we investigate the role of the nonlocal component of the exciton-exciton (dipolar) interactions on the optical response of these strongly interacting moiré exciton-polaritons under conditions of strong optical driving. We find that the nonlocal interactions can strongly influence the steady-state properties leading to multistabilities with spontaneously broken translational symmetry and pronounced distortions of the multiphoton resonances. We develop a self-consistent approach to describe the steady-state solution of moiré excitons coupled to a cavity field, treating the long-range interaction between the excitons and the photon field at the semiclassical level.