Far-infrared optical conductivity of CeCu2Si2

TL;DR

This study explores the optical properties of CeCu2Si2 across a broad energy and temperature range, revealing how heavy quasiparticle coherence develops and a gap-like feature emerges due to electron correlations.

Contribution

It provides detailed optical conductivity measurements of CeCu2Si2, demonstrating the evolution of heavy quasiparticle coherence and identifying a correlation-induced gap feature.

Findings

Narrowing of optical conductivity spectra with cooling.

Emergence of a gap-like suppression below 30 K.

Identification of strong electron correlations from hybridization.

Abstract

Journal ref.: J. Phys.: Condens. Matter 25, 065602 (2013): We investigated the optical reflectivity of the heavy-fermion metal CeCu2Si2 in the energy range 3 meV - 30 eV for temperatures between 4K - 300K. The results for the charge dynamics indicate a behavior that is expected for the formation of a coherent heavy quasiparticle state: Upon cooling the spectra of the optical conductivity indicate a narrowing of the coherent response. Below temperatures of 30 K a considerable suppression of conductivity evolves below a peak structure at 13 meV. We assign this gap-like feature to strong electron correlations due to the 4f-conduction electron hybridization.