Spin-vibronics in interacting nonmagnetic molecular nanojunctions

TL;DR

This paper investigates how molecular vibrations in nonmagnetic molecular transistors with ferromagnetic reservoirs induce an effective magnetic field, leading to spin phenomena influenced by electron interactions and phonon coupling.

Contribution

It introduces the concept of spin-vibronic effects in nonmagnetic molecular junctions, highlighting the emergence of an effective exchange magnetic field due to vibrational and many-body interactions.

Findings

Effective spin-phonon coupling arises from electron-phonon and Coulomb interactions.

Spin precession and accumulation depend on bias, gate voltages, and magnetization angles.

The study provides a theoretical framework for spin dynamics in molecular nanojunctions.

Abstract

We show that in the presence of ferromagnetic electronic reservoirs and spin-dependent tunnel couplings, molecular vibrations in nonmagnetic single molecular transistors induce an effective intramolecular exchange magnetic field. It generates a finite spin-accumulation and -precession for the electrons confined on the molecular bridge and occurs under (non)equilibrium conditions. The effective exchange magnetic field is calculated here to lowest order in the tunnel coupling for a nonequilibrium transport setup. Coulomb interaction between electrons is taken into account as well as a finite electron-phonon coupling. We show that for realistic physical parameters, an effective spin-phonon coupling emerges. It is induced by quantum many-body interactions, which are either electron-phonon or Coulomb-like. We investigate the precession and accumulation of the confined spins as function of bias- and gate-voltages as well as their dependence on the angle enclosed by the magnetizations between the left and right reservoir.