Dynamical correlations in electronic transport through a system of coupled quantum dots

Abstract

Current auto and cross correlations are studied in a system of two capacitively coupled quantum dots. We are interested in a role of Coulomb interaction in dynamical correlations, which occur outside the Coulomb blockade region (for high bias). After decomposition of the current correlation functions into contributions between individual tunneling events, we can show which of them are relevant and lead to sub-/super-Poissonian shot noise and negative/positive cross correlations. The results are differentiated for weak and strong interdot couplings. Interesting results are for the strong-coupling case when electron transfer in one of the channel is strongly correlated with charge drag in the second channel. We show that cross correlations are nonmonotonic functions of bias voltage and they are in general negative (except some cases with asymmetric tunnel resistances). This is effect of local potential fluctuations correlated by Coulomb interaction, which mimics the Pauli exclusion principle.