FINITE-SIZE EFFECTS IN A METALLIC MULTICHANNEL RING WITH KONDO IMPURITY - PERSISTENT CURRENTS AND MAGNETORESISTANCE

We consider a spin-1/2 impurity interacting with conduction electrons in two different orbital channels via an isotropic spin exchange. The exchange is the same for both channels, but a crystalline held breaks the symmetry between the orbital channels. This corresponds to a split ting of the conduction electron Gamma(8) into two doublets in the quad rupolar Kondo effect, or to the electron-assisted tunneling of an atom in a double-well potential in an external magnetic field. Another pos sible realization could be a quantum dot coupled to two equal rings of the same length subject to an electrostatic potential difference. We consider the Bethe ansatz equations for this model and derive the towe r structure of the finite size corrections to the ground-state energy. These results are used to discuss the Aharonov-Bohm-Casher interferen ce pattern in the persistent charge and spin currents, and the magneto resistivity due to the scattering of electrons off the impurity.