Spin-orbit coupling and beyond in Chiral-Induced Spin Selectivity

TL;DR

This review explores the microscopic mechanisms behind Chiral-Induced Spin Selectivity (CISS), emphasizing how molecular chirality and local electric fields enhance spin-orbit coupling to produce spin-polarized electron transport in light-element materials.

Contribution

It provides a critical analysis of existing models and introduces a field-theoretic perspective linking chirality density to spin current pseudoscalars, advancing understanding of CISS mechanisms.

Findings

Effective SOC is enhanced by molecular chirality and local electric fields.

Relativistic quantum mechanics links chirality density to spin current pseudoscalars.

Models must satisfy symmetry constraints and Onsager reciprocity.

Abstract

Chiral-Induced Spin Selectivity (CISS) describes the emergence of spin-polarized electron transport in chiral systems without magnetic fields, a remarkable effect in light-element materials with weak intrinsic spin-orbit coupling (SOC). This mini-review analyzes the microscopic origins of CISS, highlighting how molecular chirality, local electric fields, and dynamic distortions enhance effective SOC and drive spin-dependent transport. We critically assess existing models in terms of their symmetry constraints, phenomenological assumptions, and compliance with Onsager reciprocity. Recent developments combining relativistic quantum mechanics and complete multipole representations reveal a direct link between chirality density and spin current pseudoscalars, suggesting a field-theoretic foundation for CISS. These insights could help position light-element chiral nanomaterials as tunable platforms for probing and engineering spin-selective phenomena at the nanoscale.