Eur. Phys. J. B 19, 167-170 (2001)
https://doi.org/10.1007/s100510170324

Charge excitations in heavy electron metals

¹ Laboratorium für Festkörperphysik ETH-Zurich, 8093 Zurich, Switzerland
² Institut für Festkörperphysik, Technical University Darmstadt, 64283 Darmstadt, Germany
³ Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles CA 90095-1547, USA

Corresponding author: ^a degiorgi@solid.phys.ethz.ch

Received: 28 August 2000
Revised: 31 October 2000
Published online: 15 January 2001

Abstract

We show that the optical response of metals with strong electron-electron correlation consists of two excitations, a renormalized Drude response at zero energy and a mid-infrared peak occurring at frequencies around 2000 cm^-1. The latter originates from a dynamical, correlation-induced gap, as evinced from a many body theoretical approach based on the periodic Anderson model. At very low temperatures, it can be viewed as optical gap between two renormalized quasi-particle bands. The gap size is proportional to the geometric mean of the characteristic lattice Kondo temperature of the material and its bandwidth.