Kondo Resonance Effect on Persistent Currents through a Quantum Dot in a Mesoscopic Ring

The persistent current through a quantum dot inserted in a mesoscopic ring of length $L$ is studied. A cluster representing the dot and its vicinity is exactly diagonalized and embedded into the rest of the ring. It is shown that the persistent current at the Kondo regime is enhanced relative to the current flowing either when the dot is at resonance or along a perfect ring of the same length. In the Kondo regime, the current scales as $L^{-1/2\mathrm{}}$, unlike the $L^{-1\mathrm{}}$ scaling of a perfect ring. We discuss the possibility of detection of the Kondo effect by means of a persistent current measurement.