Coherent optical spin Hall transport for polaritonics at room temperature

Abstract

Spin or valley degrees of freedom hold promise for next-generation spintronics. Nonetheless, the macroscopic coherent spin current formations are still hindered by rapid dephasing due to electron scattering, specifically at room temperature. Exciton polaritons offer excellent platforms for spin-optronic devices via the optical spin Hall effect. However, this effect could neither be unequivocally observed at room temperature nor be exploited for practical spintronic devices due to the presence of strong thermal fluctuations or large linear spin splitting. Here we report the observation of room-temperature optical spin Hall effect of exciton polaritons, with the spin current flow over 60 μm in a formamidinium lead bromide perovskite microcavity. We provide direct evidence of long-range coherence in the flow of polaritons and the spin current carried by them. Leveraging the spin Hall transport of polaritons, we further demonstrate two polaritonic devices, namely, a NOT gate and a spin-polarized beamsplitter, advancing the frontier of room-temperature polaritonics in perovskite microcavities.