Vibrationally-mediated Dzyaloshinskii-Moriya interaction as the origin of Chirality-Induced Spin Selectivity in donor-acceptor molecules

TL;DR

This paper presents a theory where vibrational modes induce a Dzyaloshinskii-Moriya interaction, explaining the origin of Chirality-Induced Spin Selectivity in donor-acceptor molecules and aligning with experimental observations.

Contribution

It introduces a vibrationally-mediated Dzyaloshinskii-Moriya interaction model that explains CISS phenomena and predicts temperature and magnetic field dependencies.

Findings

High spin polarization arises from the model with realistic parameters.

The model explains magnetic field dependence observed in EPR measurements.

Numerical simulations predict a non-trivial temperature dependence of CISS.

Abstract

Chirality-induced spin selectivity (CISS) was recently observed in photo-excited donor-chiral bridge-acceptor molecules, but a predictive theory able to explain available experiments is still lacking. Here we show that low-energy torsional modes modulating hopping and spin-orbit coupling give rise to a Dzyaloshinskii-Moriya interaction between the transferred electron and the one sitting on the donor, producing high spin polarization for perfectly realistic parameters. Our model introduces a low energy scale in the spin dynamics which explains the magnetic field dependence observed in EPR measurements and predicts a non-trivial temperature dependence, as demonstrated by numerical simulations. The present theory lays the foundations for future test-bed experiments and for the design of applications in spintronics and quantum technologies.