Dynamical polarization processes in double quantum dots coupled in series

The polarization processes in a system of double quantum dots coupled in series with electrodes are studied in the limit of sequential tunnelling. The Coulomb interactions of accumulated charges on both quantum dots and the competition between dot-dot and dot-electrode coupling are responsible for the non-monotonic filling of each dot, which leads to a change of the sign of the polarization as a function of bias voltage. We show that this dynamical switching polarization effect is common and observable in various multidot systems.