Spin Polarization through A Molecular Junction Based on Nuclear Berry Curvature Effects

TL;DR

This paper investigates how nuclear Berry curvature influences spin polarization in molecular junctions, revealing that nuclear motion can induce significant spin-polarized electronic currents even under dissipation.

Contribution

It demonstrates the role of nuclear Berry curvature in generating spin polarization in molecular junctions, linking nuclear dynamics to electronic spin effects in nonequilibrium conditions.

Findings

Significant spin polarization of electronic current due to nuclear Berry curvature.

Different nuclear wave packets experience distinct pseudo-magnetic fields.

Spin separation persists despite dissipation mechanisms.

Abstract

We explore the effects of spin-orbit coupling on nuclear wave packet motion near an out-of-equilibrium molecular junction, where nonzero Berry curvature emerges as the antisymmetric part of the electronic friction tensor. The existence of nonzero Berry curvature mandates that different nuclear wave packets (associated with different electronic spin states) experience different nuclear Berry curvatures, i.e. different pseudo-magnetic fields. Furthermore, for a generic, two-orbital two-lead model (representing the simplest molecular junction), we report significant spin polarization of the {\em electronic} current with decaying and oscillating signatures in the large voltage limit -- all as a result of {\em nuclear} motion. These results are consistent with magnetic AFM chiral-induced spin selectivity experiments. Altogether, our results highlight an essential role for Berry curvature in condensed phase dynamics, where spin separation survives dissipation to electron-hole pair creation and emerges as one manifestation of nuclear Berry curvature.