Chirality-induced Spin-Orbit Coupling and Spin Selectivity

TL;DR

This paper demonstrates that the curvature of a helical path induces spin-orbit coupling, which, combined with broken time-reversal symmetry, may explain the Chirality-induced Spin Selectivity (CISS) effect observed in chiral molecules.

Contribution

It introduces the concept of chirality-induced spin-orbit coupling ($ ext{χ}$-SOC) as a key factor in understanding the microscopic origin of CISS.

Findings

$ ext{χ}$-SOC magnitude aligns with values in helical molecular structures

Chirality-induced spin-orbit coupling can produce significant spin polarization

Broken time-reversal symmetry enhances the spin selectivity effect

Abstract

We show that a spinor traveling along a one-dimensional helical path develops a spin-orbit coupling as a result of the curvature of the path. We estimate the magnitude of the associated spin polarization and obtain values typical of many helical molecular structures that showcase the Chirality-induced Spin Selectivity (CISS) effect. We find that this chirality-induced spin-orbit coupling ($\chi$-SOC), in conjunction with broken time-reversal symmetry, may be an important ingredient for the microscopic underpinning of the CISS phenomenon.