Enhancement of Chiral-Induced Spin Selectivity via Circularly Polarized Light

Although the chiral-induced spin selectivity (CISS) effect was discovered in 1999, the practical applications of the CISS effect face challenges due to relatively low spin polarization. Here, we report that circularly polarized light (CPL) can significantly enhance the CISS effect through indirect strong light–matter interactions. In particular, we show that the light-induced Berry force can strongly affect nuclear motion, resulting in spin selectivity from near 0 to almost 100%. Our results demonstrate that the spin–orbit couplings alone cannot explain the large spin selectivity in observed experiments, and nonadiabatic effects from electron–nuclear couplings and electron–photon couplings should be incorporated into the CISS modeling. The theory we developed can be used as the design principle for experimentally controlling CISS effects using CPL.