Vibration-induced Kondo tunneling through metal-organic complexes with even electron occupation number

TL;DR

This paper explores how vibrational modes in a metal-organic complex can induce Kondo tunneling effects, revealing new mechanisms for electron transport in molecular electronics.

Contribution

It demonstrates that molecular vibrations can enable Kondo effects in systems with a singlet ground state, expanding understanding of vibrationally assisted electron transport.

Findings

Vibrational modulation induces Kondo effect in singlet-triplet systems

Single-phonon and two-phonon processes facilitate co-tunneling

Potential for experimental observation of vibrationally induced Kondo phenomena

Abstract

We investigate transport through a mononuclear transition-metal complex with strong tunnel coupling to two electrodes. The ground state of this molecule is a singlet while the first excited state is a triplet. We show that a modulation of the tunnel-barrier due to a molecular distortion which couples to the tunneling induces a Kondo-effect, provided the discrete vibrational energy compensates the singlet/triplet gap. We discuss the single-phonon and two-phonon assisted co-tunneling and possible experimental realization of the theory.