INTERPLAY OF MAGNETISM AND IMPURITY BAND IN A KONDO INSULATOR

We consider Kondo holes in a Kondo insulator described by the symmetri c Anderson lattice within the mean-field approximation in terms of fou r slave-bosons per site. Each Kondo hole introduces a bound state in t he hybridization gap and a finite concentration of Kondo holes gives r ise to an impurity band. The impurity band reduces the threshold for t he antiferromagnetic instability displaying re-entrance as a function of Kondo hole concentration, but does not substantially affect ferroma gnetism.