KONDO EFFECT ON TUNNELING CURRENTS IN A MESOSCOPIC RING

We study the effect of the Kondo resonance on the tunneling current os cillations in a mesoscopic ring with a quantum dot, threaded by an ext ernal magnetic flux. Two situations are considered: the isolated ring and the ring connected to two external contacts. The system is describ ed by an Anderson impurity tight-binding Hamiltonian where the electro n-electron interaction is restricted to the dot. It is shown that at l ow temperature, even with the system out of resonance, the Kondo peak provides a channel for the electron to tunnel through the dot giving r ise to persistent currents, for the isolated ring and to the Bohm-Ahar onov oscillations, for the ring electrically connected. (C) 1998 Elsev ier Science B.V. All rights reserved.