Low-energy scale of the periodic Anderson model

Abstract

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 ${T}_{K};$ ${T}_{0}{/T}_{K}\ensuremath{\propto}\mathrm{exp}{1/3I},$ 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 Nozi\`eres' 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 Nozi\`eres, we find that the ${T}_{0}\ensuremath{\propto}{T}_{K}$ with a coefficient that depends strongly on conduction-band filling.