Low-energy scale of the periodic Anderson model

Wilson's numerical renormalization-group method is used to study the paramagnetic ground state of the periodic Anderson model within the dynamical mean-field approach. For the particle-hole symmetric model, which is a Kondo insulator, we find that the lattice Kondo scale T-O is strongly enhanced over the impurity scale T-K; T-0/T(K)proportional to exp{1/31}, where I is the Schrieffer-Wolff exchange coupling. In the metallic regime, where the conduction-band filling is reduced from one, we find characteristic signatures of Nozieres' exhaustion scenario, including a strongly reduced lattice Kondo scale, a significant suppression of the states available to screen the S-electron moment, and a Kondo resonance with a strongly enhanced height. However, in contrast to the quantitative predictions of Nozieres, we find that the T(0)proportional to T-K with a coefficient that depends strongly on conduction-band filling.