Nonequilibrium electron transport in strongly correlated molecular junctions

TL;DR

This paper models electron transport in molecular junctions, revealing how phonon interactions influence Kondo resonance and lead to negative differential resistance, advancing understanding of inelastic transport phenomena.

Contribution

It introduces a HOMO-LUMO model with Anderson-Holstein interaction to explain inelastic transport features in molecular junctions, including phonon-assisted Kondo resonance.

Findings

Co-tunneling conductance peak near Kondo resonance due to phonons

Resonance re-emergence facilitated by phonon excitations at phonon frequency

Negative differential resistance observed when resonance is destroyed

Abstract

We investigate models of molecular junctions which constitute minimal Hamiltonians to account for zero-bias-anomaly and the satellite features of inelastic transport by molecular phonons. Through nonlinear transport calculations with the imaginary-time nonequilibrium formalism, a HOMO-LUMO model with Anderson-Holstein interaction is shown to produce co-tunneling conductance peak in the vicinity of Kondo resonance which is mediated by a re-emergent many-body resonance assisted by phonon excitations at bias equal to the phonon frequency. Destruction of the resonance leads to negative-differential-resistance in the sequential tunneling regime.