Chirality-induced spin selectivity (CISS) is an effect that has recently attracted a great deal of attention in chiral chemistry and that remains to be understood. In the CISS effect, electrons passing through chiral molecules acquire a large degree of spin polarization. In this work we study the case of atomically-thin chiral crystals created by van der Waals assembly. We show that this effect can be spectacularly large in systems containing just two monolayers, provided they are spin-orbit coupled. Its origin stems from the combined effects of structural chirality and spin-flipping spin-orbit coupling. We present detailed calculations for twisted homobilayer transition metal dichalcogenides, showing that the chirality-induced spin polarization can be giant, e.g. easily exceeding 50% for MoTe2. Our results clearly indicate that twisted quantum materials can operate as a fully tunable platform for the study and control of the CISS effect in condensed matter physics and chiral chemistry.
@article{arxiv.2312.09169,
title = {Giant chirality-induced spin polarization in twisted transition metal dichalcogenides},
author = {Guido Menichetti and Lorenzo Cavicchi and Leonardo Lucchesi and Fabio Taddei and Giuseppe Iannaccone and Pablo Jarillo-Herrero and Claudia Felser and Frank H. L. Koppens and Marco Polini},
journal= {arXiv preprint arXiv:2312.09169},
year = {2025}
}