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 $T_0$ is strongly enhanced over the impurity scale $T_K;$ $T_0{/T}_K\propto \exp \{1/3I\},$ 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 Nozières’ exhaustion scenario, including a strongly reduced lattice Kondo scale, a significant suppression of the states available to screen the f-electron moment, and a Kondo resonance with a strongly enhanced height. However, in contrast to the quantitative predictions of Nozières, we find that the $T_0\propto T_K$ with a coefficient that depends strongly on conduction-band filling.