On the mean-field theory of antiferromagnetically ordered Kondo lattices

The experimentally observed antiferromagnetic correlation in the heavy-fermion compounds is incorporated into the 1/N Slave-Boson (SB) approach, where N is the ground-state degeneracy. At mean-field level this generates a staggered internal field (δ) via itinerant exchange with the conduction electrons and modifies the one-body energy of the magnetic impurity electrons on different sublattices. Standard SB procedures are followed to obtain the mean-field equations for the occupation and the renormalized one-body energy of the impurity electrons. It is shown that for the band structure and electron filling of heavy-fermion compounds this staggered field lowers the ground-state energy more than a uniform field by opening up a gap at the Brillouin Zone boundary. From the self-consistent equation for the sublattice magnetization a criterion for the occurence of this magnetic ordering is determined. (orig.)