Exciton

Exciton-polaritons

Physics

Acoustics

Biexciton

Lattice (music)

Bose–Einstein condensate

Condensed matter physics

Polariton

Nature Physics

Exciton polaritons, with extremely low effective mass1, are regarded as promising candidates to realize Bose–Einstein condensation in lattices for quantum simulations2 towards room-temperature operations3–8. Along with the condensation, an efficient exciton polariton quantum simulator9 would require a strong lattice with robust polariton trapping as well as strong intersite coupling to allow coherent quantum motion of polaritons within the lattice. A strong lattice can be characterized with a larger forbidden bandgap opening and a larger lattice bandwidth compared with the linewidth. However, exciton polaritons in such strong lattices have only been shown to condense at cryogenic temperatures3–8. Here, we report the observation of non-equilibrium exciton polariton condensation in a one-dimensional strong lead halide perovskite lattice at room temperature. Modulated by deep periodic potentials, the strong lead halide perovskite lattice exhibits a large forbidden bandgap opening up to 13.3 meV and a lattice band up to 8.5 meV wide, which are at least 10 times larger than previous systems. Above a critical density, we observe polariton condensation into py orbital states with long-range spatial coherence at room temperature. Our result opens the route to the implementation of polariton condensates in quantum simulators at room temperature. Non-equilibrium Bose–Einstein condensation of exciton polaritons in chains of lead halide perovskite pillars can occur at room temperature. These condensates have long spatial coherence.

Observation of exciton polariton condensation in a perovskite lattice at room temperature