Spin-flip scattering in chiral induced spin selectivity using the Riccati equation

TL;DR

This paper models electron and spin transport in chiral molecules using Riccati equations, revealing that spin-flip scattering has a minor role in the observed spin selectivity effect, and providing a framework to interpret experimental data.

Contribution

It introduces an analytical approach using Riccati equations to analyze spin-flip scattering in chiral molecules, clarifying its limited impact on CISS.

Findings

Spin-flip scattering is minor in experimentally studied systems.

The Riccati equation approach enables interpretation of spin-filter strength.

The model can be applied to experimental and quantum data.

Abstract

The chiral induced spin selectivity (CISS) in layers of helical molecules gained considerable attention in the emerging field of spintronics, because the effect enables spin-filter devices under ambient conditions. Several theoretical studies have been carried out to explain this effect on a microscopic scale, but the origin of the effect is still controversial. In particular the role of spin-flip scattering during electron transport is an open issue. In this study we describe the electron and spin transport by rate equations including spin-dependent losses and spin-flip scattering. We reduce the problem to the solution of the Riccati differential equation to obtain analytical solutions. The results allow to determine and interpret the strength and scalability of CISS based spin-filters from experimental data or quantum mechanical models. For the helical systems studied experimentally so far it turns out that spin-flip scattering plays a minor role.