Transport in coupled quantum dots: Kondo effect versus antiferromagnetic correlation

The interplay between the Kondo effect and the interdot magnetic interactio n in a coupled-dot system is studied. An exact result for the transport pro perties at zero temperature is obtained by diagonalizing a cluster, compose d by the double dot and its vicinity, which is connected to leads. It is sh own that the system goes continuously from the Kondo regime to an antiferro magnetic state as the interdot interaction is increased. The conductance, t he charge at the dots, and the spin-spin correlation are obtained as a func tion of the gate potential.