Phonon-assisted Kondo Effect in a Single-Molecule Transistor out of Equilibrium

TL;DR

This paper explores how electron-phonon interactions influence the Kondo effect in a single-molecule transistor under nonequilibrium conditions, revealing asymmetric phonon satellites and spin-dependent phenomena.

Contribution

It introduces an improved theoretical scheme to analyze the combined effects of electron-phonon coupling and Kondo physics in nonequilibrium transport.

Findings

Identification of two types of Kondo phonon-satellites with asymmetric shapes

Disappearance of spin-resolved Kondo satellites under Zeeman splitting

Explanation of nonlinear conductance signatures with a clear physical picture

Abstract

The joint effect of the electron-phonon interaction and Kondo effect on the nonequilibrium transport through the single molecule transistor is investigated by using the improved canonical transformation scheme and extended equation of motion approach. Two types of Kondo phonon-satellites with different asymmetric shapes are fully confirmed in the spectral function, and are related to the electron spin singlet or hole spin singlet, respectively. Moreover, when a moderate Zeeman splitting is caused by a local magnetic field, the Kondo satellites in the spin resolved spectral function are found disappeared on one side of the main peak, which is opposite for different spin component. All these peculiar signatures that manifest themselves in the nonlinear differential conductance, are explained with a clear physics picture.