Spin selective transport through helical molecular systems

TL;DR

This paper demonstrates significant spin-selective electron transport in helical molecular systems using a minimal model, highlighting the roles of Rashba-like spin-orbit interaction and low electronic dispersion.

Contribution

It introduces a minimal model showing how weak spin-orbit coupling and helical symmetry induce spin selectivity in molecular systems.

Findings

Spin selectivity is significant even with weak spin-orbit coupling.

Helical symmetry and low dispersion are key factors for selectivity.

Results are expected to be generic for chiral molecules with low conductivity.

Abstract

Highly spin selective transport of electrons through a helically shaped electrostatic potential is demonstrated in the frame of a minimal model approach. The effect is significant even in the case of weak spin-orbit coupling. Two main factors determine the selectivity, an unconventional Rashba- like spin-orbit interaction, reflecting the helical symmetry of the system, and a weakly dispersive electronic band of the helical system. The weak electronic coupling, associated with the small dispersion, leads to a low mobility of the charges in the system and allows even weak spin-orbit interactions to be effective. The results are expected to be generic for chiral molecular systems displaying low spin-orbit coupling and low conductivity.