Interplay between the Correlations and Superconductivity in Electron Transport through the Double Quantum Dots

We study the influence of electron correlations on nonequilibrium transport through the quantum dots coupled between one metallic and one superconducting electrode. Such type of nanodevices are characterized by the induced on-dot pairing spread from the superconducting lead (proximity effect) and effectively responsible for mixing the particle with hole excitations. On the other hand, strong Coulomb repulsion between the opposite spin electrons tends to suppress a double occupancy of the quantum dots competing with the on-dot superconducting order. The Coulomb interactions can also cause a screening of the quantum dot spin by itinerant electrons of the metallic lead giving rise to formation of the Kondo resonance. We analyze interplay of such phenomena for the setup of double quantum dots where the quantum interference (such as Fano) effects influence the subgap electron transport through the Andreev scattering.