Nonstationary theory of magnetic field induced current for molecular spin nanojunction

TL;DR

This paper develops a nonstationary theoretical framework for understanding magnetic field-induced current in molecular spin nanojunctions, incorporating electron and energy transfer mechanisms and magnetic control strategies.

Contribution

It introduces a novel nonstationary theory combining electron transfer, energy transfer, and magnetic control in molecular spin nanojunctions, with analytical and numerical solutions.

Findings

Magnetic field can enhance charge transfer in spin nanojunctions.

Derived a set of differential equations for molecular and electronic variables.

Presented analytical and numerical solutions for current dynamics.

Abstract

For the study of molecular spin junctions, we take into account two types of couplings between the molecule and the metal leads: (i) electron transfer that gives rise to net current in the biased junction and (ii) energy transfer between the molecule and the leads. Using a rotating wave approximation in the Heisenberg representation, we derive a set of differential equations for the expectation values of relevant variables: electron and phonon populations and molecular polarization. A magnetic field control method to enhance the charge transfer at spin nanojunctions, which characterizes the molecule feature, is discussed. An approximate analytical solution of the resulting dynamical equation is supported by numerical solution. The magnetic control by charge transfer is described by transient pseudo-fermions of electrons interacting with spins. The rapid adiabatic passage of the energy between the molecule and the leads is taken into account. The current for molecular spin nanojunctions is derived.