Experiments have shown that chiral organic molecules can act as electron spin filters, an effect termed chiral-induced spin selectivity. The lack of a theoretical explanation for its origin and the availability of only indirect evidence for the spin polarization has hampered its development though.

Feature papers

Spin-polarized electron transmission in DNA-like systems
M. A. Sierra, D. Sánchez, R. Gutierrez, G. Cuniberti, F. Domínguez-Adame and E. Díaz
Biomolecules 10, 49 (2020)

The helical distribution of the electronic density in chiral molecules, such as DNA and bacteriorhodopsin, has been suggested to induce a spin–orbit coupling interaction that may lead to the so-called chirality-induced spin selectivity (CISS) effect. Key ingredients for the theoretical modelling are, in this context, the helically shaped potential of the molecule and, concomitantly, a Rashba-like spin–orbit coupling due to the appearance of a magnetic field in the electron reference frame. Symmetries of these models clearly play a crucial role in explaining the observed effect, but a thorough analysis has been largely ignored in the literature. In this work, we present a study of these symmetries and how they can be exploited to enhance chiral-induced spin selectivity in helical molecular systems.