Effect of band filling in the Kondo lattice: A mean-field approach

The usual Kondo lattice, including an antiferromagnetic exchange interactio n between nearest-neighboring localized spins, is treated here in a mean-fi eld scheme that introduces two mean-field parameters: one associated with t he local Kondo effect, and the other related to the magnetic correlations b etween localized spins. Phases with short-range magnetic correlations or co existence between those and the Kondo effect are obtained. By varying the n umber of electrons in the conduction band, we notice that the Kondo effect tends to be suppressed away from half filling, while magnetic correlations can survive if the Heisenberg coupling is strong enough. An enhanced linear coefficient of the specific heat is obtained at low temperatures in the me tallic state. [S0163-1829(99)00534-2].