Chiral induced Spin Polarized Electron Current: Origin of the Chiral Induced Spin Selectivity Effect

TL;DR

This paper provides a theoretical explanation for the chiral induced spin selectivity effect, emphasizing the necessity of molecular chirality and dissipation for spin polarization in chiral molecules.

Contribution

It identifies the fundamental conditions—chirality and dissipation—required for the effect to occur, advancing understanding of its origin.

Findings

Chirality is necessary for breaking spin-degeneracy in molecules without heavy elements.

Dissipation is essential for molecules to develop spin polarization.

Both chirality and dissipation must be coordinated for the effect to emerge.

Abstract

The discovery of the chiral induced spin selectivity effect has provided a novel tool to study how active physical and chemical mechanism may differ in chiral enantiomers, however, the origin of the effect itself is yet an open question. In this article, it is theoretically shown that two aspects have to be fulfilled for the chiral induced spin selectivity effect to arise. First, chirality is a necessary condition for breaking spin-degeneracy in molecular structures that do not comprise heavy elements. Second, dissipation is indispensable for the molecule to develop a non-vanishing spin-polarization. These theoretical conclusions are illustrated in terms of a few examples, showing the necessity of the two aspects to be coordinated for the emergence of the chiral induced spin selectivity effect.