TITLE: Transmittance through an Aharonov - Bohm ring with embedded quantum
             dot described by Kondo Hamiltonian

ABSTRACT:
 

Kondo physics of quantum dots together with the transmittance phase behavior are of considerable current interest, both experimentally and theoretically. The presence of magnetic impurities in the Q.D. produces new effects (like the spin-flip scattering) due to the exchange interaction between the spin of the conducting electrons and the localized spins.

We numerically find the complex transmittance of a Q.D. directly connected to leads or embedded in an A-B ring, as in recent experimental devices used to calculate the phase (whose behaviorhas not been fully understood). The magnetic flux through the ring and gate potential applied on the dot are varied. Certainresonances (of the dot) split when the exchange parameter is increased.

The spin-conserving and spin-flip transmittance exhibit A-B oscillations and the Fourier analysis of these oscillations show specific features compared to the typical periodicity of the usual A-B effect in rings.

We use a tight-binding model for the Kondo Hamiltonian and the Landauer-Buttiker transport formalism for the ring-dot system.

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