Chiral cavity induced spin selectivity

Abstract

Chiral-induced spin selectivity (CISS) is a phenomenon in which electron spins are polarized as they are transported through chiral molecules, and the spin polarization depends on the handedness of the chiral molecule. In this study, we show that spin selectivity can be realized in achiral materials by coupling electrons to a single mode of a chiral optical cavity. By investigating spin-dependent electron transport using the nonequilibrium Green's function approach, the spin polarization in a two-terminal setup is demonstrated to approach unity if the rate of dephasing is sufficiently small and the average chemical potential of the two leads is within an appropriate range of values, which is narrow because of the high frequency of the cavity mode. To obtain a wider range of energies for a large spin polarization, we propose to combine the CISS in chiral molecules with the light-matter interactions. For demonstration, the spin polarization of electrons transported through a helical molecule strongly coupled to a chiral cavity mode is evaluated.