Effects of TE–TM splitting on bistability and nonlinear spin dynamics in resonantly driven spinor exciton-polaritons

We investigate the influence of transverse-electric–transverse-magnetic (TE–TM) splitting on the nonlinear response and bistability of resonantly driven spinor exciton-polaritons in a spatially homogeneous microcavity system. Using a coupled exciton–photon mean-field model, we find that TE–TM splitting significantly modifies the bistability threshold, hysteresis width, and spin composition of the steady states. In particular, TE–TM splitting counteracts the spin imbalance imposed by elliptically polarized pumping, leading to nearly equal populations of the two spin components and strongly suppressed degree of circular polarization in the steady state. The pump momentum plays a crucial role through its connection to the curvature of the lower polariton dispersion, resulting in distinct nonlinear regimes with different switching thresholds and dynamical responses. The intermediate branch within the hysteresis loop is unstable but may exhibit slow instability growth rates, giving rise to long-lived transient states. These results clarify how TE–TM splitting reshapes bistability and nonlinear spin dynamics in polariton systems and provide insight into the controlling polariton switching behavior through cavity anisotropy and pump parameters.