Towards the understanding of Chirality Induced Spin Selectivity

Chirality-induced spin selectivity (CISS) indicates a wide variety of phenomena occurring in chiral media, where the spin orientation of an electron affects its behavior. CISS was first observed, [1] more than 30 years ago, in photoemission experiments that revealed significant asymmetry in scattering probabilities as spin-polarized electrons were driven through a thin layer of chiral molecules. Nowadays, various experiments have demonstrated remarkable efficiency in spin filtration, even at the singlemolecule level[2] Driven by the potential for applications in fields such as quantum technologies, spintronics, and enantioselective chemistry, tremendous efforts have been devoted to elucidate the mechanism behind CISS, without reaching a quantitative agreement with experiments. In this work, we investigate CISS in electron transport, relying on a modified Hubbard model to include spin-orbit coupling (SOC). Specifically, current is driven through the system via the current-constrained approach to achieve a steady-state condition where spin current and spin polarization can be directly observed. We analyze the role of the connectivity among the sites, of vibrational degrees of freedom as well as of two-electron terms in the SOC operator, beyond the standard mean-field approximation.