Suppression of current in transport through parallel double quantum dots

We report our study of $I-V$ curves in the transport through the quantum dot when an additional quantum dot lying in the Kondo regime is side-connected to it. Due to the Kondo scattering of the effective spin on a side-connected quantum dot, the conductance is suppressed at low temperatures and at low source-drain bias voltages. This zero-bias anomaly is understood as enhanced Kondo scattering with decreasing temperature.