Electrically Generated Exciton Polaritons with Spin On‐Demand

Generation and manipulation of exciton polaritons with controllable spin could deeply impact spintronic applications, quantum simulations, and quantum information processing, but is inherently challenging due to the charge neutrality of the polariton and the device complexity it requires. Here, electrical generation of spin‐polarized exciton polaritons in a monolithic dielectric perovskite metasurface embedded in a light‐emitting transistor is demonstrated. A finely tailored interplay of in‐ and out‐of‐plane symmetry breaking of the metasurface allows to lift the spin degeneracy through the polaritonic Rashba effect, yielding high spin purity with normalized Stokes parameter of S3 ≈ 0.8. Leveraging on spin‐momentum locking, the unique metatransistor device architecture enables electrical control of spin and directionality of the polaritonic emission. Here, the development of compact and tunable spintronic devices is advanced and an important step toward the realization of electrically pumped inversionless spin‐lasers is represented.