COQBLIN-SCHRIEFFER IMPURITY IN A ONE-DIMENSIONAL CORRELATED ELECTRON LATTICE

We consider electrons of effective spin S on a chain with nearest-neig hbour hopping t constrained by the excluded multiple occupancy of the lattice sites, and spin exchange J between neighbouring sites. The spi n space of the model is SU(2S + 1) invariant, and at the supersymmetri c point, J = t, the charge and the spin play identical roles forming a n integrable SU(2S + 2) superalgebra. Without compromising the integra bility we introduce a Coqblin-Schrieffer-like impurity of spin S, whic h interacts with the correlated conduction states of the host. The dis crete Bethe ansatz equations diagonalizing the host with impurity are derived and the ground-state properties of the impurity are studied as a function of the Kondo exchange coupling. An undercompensated impuri ty of spin S embedded into a chain of interacting spin- 1/2 electrons is also discussed.