Chirality-controlled spin scattering through quantum interference

TL;DR

This paper presents a simple analytical model demonstrating how quantum interference in a helical atomic structure can lead to spin-selective scattering, providing a potential explanation for chirality-induced spin selectivity.

Contribution

The authors introduce an analytically solvable model showing how spin-dependent scattering arises from quantum interference in a chiral-like system, offering insights into the underlying mechanism.

Findings

Forward scattering is spin-independent.

Back scattering exhibits spin dependence over wide energy ranges.

The model reveals a mechanism potentially operative in chiral systems.

Abstract

Chirality-induced spin selectivity has been reported in many experiments, but a generally accepted theoretical explanation has not yet been proposed. Here, we introduce a simple model system of a straight cylindrical free-electron wire, containing a helical string of atomic scattering centers, with spin-orbit interaction. The advantage of this simple model is that it allows deriving analytical expressions for the spin scattering rates, such that the origin of the effect can be easily followed. We find that spin-selective scattering can be viewed as resulting from constructive interference of partial waves scattered by the spin-orbit terms. We demonstrate that forward scattering rates are independent of spin, while back scattering is spin dependent over wide windows of energy. Although the model does not represent the full details of electron transmission through chiral molecules, it clearly reveals a mechanism that could operate in chiral systems.