Spin polarization through a molecular junction based on nuclear Berry curvature effects

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 pseudomagnetic fields. Furthermore, for a generic, two-orbital two-lead model (representing the simplest molecular junction), we report significant spin polarization of the electronic current with decaying and oscillating signatures in the large voltage limit---all as a result of 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.