Transient dynamics in interacting nanojunctions within self-consistent perturbation theory

TL;DR

This paper introduces a new numerical method to analyze the transient electronic and transport behavior of nanojunctions with interactions, revealing how correlations influence bistability and Kondo effects.

Contribution

A novel self-consistent numerical approach for non-equilibrium Green functions enables efficient analysis of transient dynamics in interacting nanojunctions.

Findings

Good agreement with exact results even at high interaction strengths

Correlation effects tend to suppress charge bistability

Method allows study of Kondo correlations buildup over time

Abstract

We present an analysis of the transient electronic and transport properties of a nanojunction in the presence of electron-electron and electron-phonon interactions. We introduce a novel numerical approach which allows for an efficient evaluation of the non-equilibrium Green functions in the time domain. Within this approach we implement different self-consistent diagrammatic approximations in order to analyze the system evolution after a sudden connection to the leads and its convergence to the steady state. These approximations are tested by comparison with available numerically exact results, showing good agreement even for the case of large interaction strength. In addition to its methodological advantages, this approach allows us to study several issues of broad current interest like the build up in time of Kondo correlations and the presence or absence of bistability associated with electron-phonon interactions. We find that, in general, correlation effects tend to remove the possible appearance of charge bistability.