Non-equilibrium renormalised contacts for transport in nanodevices with interaction: a quasi-particle approach

TL;DR

This paper introduces a formalism using non-equilibrium Green's functions to analyze quantum transport in interacting nanoscale junctions, revealing bias-dependent renormalization effects on contacts and conductance features.

Contribution

It applies a new self-consistent quasi-particle approach to model electron-vibron interactions and contact renormalization in nanoscale transport, extending previous methods.

Findings

Bias-dependent non-equilibrium renormalization of contacts.

Modification of conductance resonance peaks and vibron side-bands.

Effective treatment of crossing interactions in quantum transport.

Abstract

We present an application of a new formalism to treat the quantum transport properties of fully interacting nanoscale junctions. We consider a model single-molecule nanojunction in the presence of two kinds of electron-vibron interactions. In terms of the electron density matrix, one interaction is diagonal in the central region and the second off-diagonal between the central region and the left electrode. We use a non-equilibrium Green's function technique to calculate the system's properties in a self-consistent manner. The interaction self-energies are calculated at the Hartree-Fock level in the central region and within a dynamical mean-field-like approach for the crossing interaction. Our calculations are performed for different transport regimes ranging from the far off-resonance to the quasi-resonant regime, and for a wide range of parameters. They show that a non-equilibrium (i.e. bias dependent) dynamical (i.e. energy dependent) renormalisation is obtained for the contact between the left electrode and the central region in the form of a non-equilibrium renormalisation of the lead embedding potential. The conductance is affected by the renormalisation of the contact: the amplitude of the main resonance peak is modified as well as `the lineshape of the first vibron side-band.