Shot noise in transport through "double quantum dots"

TL;DR

This paper investigates shot noise in electron transport through double quantum dots, revealing how internal structure and asymmetries influence noise characteristics, with implications for experimental parameter characterization.

Contribution

It provides a detailed theoretical analysis of shot noise in double quantum dots, including effects of asymmetries and Coulomb interactions, aiding experimental interpretation.

Findings

Super-Poissonian noise appears in Coulomb blockade region.

Asymmetries lead to super-Poissonian noise and negative differential conductance.

Noise characteristics depend on internal level structure and coupling asymmetries.

Abstract

Motivated by activities of several experimental groups we investigate electron transport through two coherent, strongly coupled quantum dots ("double quantum dots"), taking into account both intra- and inter-dot Coulomb interactions. The shot noise in this system is very sensitive to the internal electronic level structure of the coupled dot system and its specific coupling to the electrodes. Accordingly a comparison between experiments and our predictions should allow for a characterization of the relevant parameters. We discuss in detail the effect of asymmetries, either asymmetries in the couplings to the electrodes or a detuning of the quantum dot levels out of resonance with each other. In the Coulomb blockade region super-Poissonian noise appears even for symmetric systems. For bias voltages above the sequential tunneling threshold super-Poissonian noise and regions of negative differential conductance develop if the symmetry is broken sufficiently strongly.