Strongly correlated regimes in a double quantum dot device

The transport properties of a double quantum dot device with one of the dots coupled to perfect conductors are analyzed using the numerical renormalization group technique and slave-boson mean-field theory. The coupling between the dots strongly influences the transport through the system, leading to a nonmonotonic dependence of the conductance as a function of the temperature and the magnetic field. For small interdot coupling and parameters such that both dots are in the Kondo regime, there is a two-stage screening of the dot's magnetic moments that is reflected in the conductance. In an intermediate-temperature regime Kondo correlations develop on one of the dots and the conductance is enhanced. At low temperatures the Kondo effect takes place on the second dot, leading to a singlet ground state in which the conductance is strongly suppressed.