Tunneling through nanosystems: Combining broadening with many-particle states

TL;DR

This paper introduces a novel Liouville equation-based method for quantum transport in nanosystems, fully accounting for Coulomb interactions and level broadening, applicable across various biases and temperatures above the Kondo temperature.

Contribution

It develops a comprehensive approach combining many-particle states with level-broadening effects, extending standard models for quantum transport analysis.

Findings

Good agreement with existing methods in their regimes of validity

Applicable to arbitrary bias and temperatures above the Kondo temperature

Provides a general expression for the density matrix elements

Abstract

We suggest a new approach for transport through finite systems based on the Liouville equation. By working in a basis of many-particle states for the finite system, Coulomb interactions are taken fully into account and correlated transitions by up to two different contact states are included. This latter extends standard rate equation models by including level-broadening effects. The main result of the paper is a general expression for the elements of the density matrix of the finite size system, which can be applied whenever the eigenstates and the couplings to the leads are known. The approach works for arbitrary bias and for temperatures above the Kondo temperature. We apply the approach to standard models and good agreement with other methods in their respective regime of validity is found.