The effect of the interdot Coulomb interaction on Kondo resonances in series-coupled double quantum dots

► When the interdot Coulomb repulsion is ignored, our results are consistent with other works. ► When U≠0, the Kondo resonance is compressed in the equilibrium case, but is enhanced in the non-equilibrium case. ► The interdot Coulomb repulsion is one of the important parameters that controls transport phenomena. ► The rich physical behaviour of DQD systems can be attributed to the interdot Coulomb repulsion.