Kondo-Fano Effect in Double Quantum Dot Side Attached to a Pair of Wires

Electron tunneling through a double quantum dot side coupled to a pair of leads is examined in finite-U slave boson mean field approach. Both the two-impurity Kondo regime at half filling and one-and three-electron Kondo effects are analyzed. Special attention is paid to the case when one of the dots is coupled to ferromagnetic lead and another to nonmagnetic. Depending on the gate voltage, the same or opposite sign of polarizations of conductance of the leads is observed.