Shot noise in transport through two coherent strongly coupled quantum dots

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.