Strongly enhanced shot noise in chains of quantum dots

TL;DR

This paper investigates charge transport in a quantum dot chain, revealing that dominant non-local Coulomb interactions lead to strongly enhanced super-Poissonian shot noise, even in symmetric systems, due to competing transport channels.

Contribution

It demonstrates that non-local Coulomb interactions can cause significant shot noise enhancement in quantum dot chains, a novel finding in fully symmetric systems.

Findings

Shot noise is strongly enhanced above the sequential tunneling threshold.

The current remains unchanged despite the noise enhancement, indicating super-Poissonian noise.

The behavior arises from competition between slow and fast transport channels due to non-local interactions.

Abstract

We study charge transport through a chain of quantum dots. The dots are fully coherent among each other and weakly coupled to metallic electrodes via the dots at the interface, thus modelling a molecular wire. If the non-local Coulomb interactions dominate over the inter-dot hopping we find strongly enhanced shot noise above the sequential tunneling threshold. The current is not enhanced in the region of enhanced noise, thus rendering the noise super-Poissonian. In contrast to earlier work this is achieved even in a fully symmetric system. The origin of this novel behavior lies in a competition of "slow" and "fast" transport channels that are formed due to the differing non-local wave functions and total spin of the states participating in transport. This strong enhancement may allow direct experimental detection of shot noise in a chain of lateral quantum dots.