Optical Evidence of Itinerant-Localized Crossover of $4f$ Electrons in Cerium Compounds

Abstract

Cerium (Ce)-based heavy-fermion materials have a characteristic double-peak structure (mid-IR peak) in the optical conductivity [$\sigma (\omega )$] spectra originating from the strong conduction ($c$)--$f$ electron hybridization. To clarify the behavior of the mid-IR peak at a low $c$-$f$ hybridization strength, we compared the $\sigma (\omega )$ spectra of the isostructural antiferromagnetic and heavy-fermion Ce compounds with the calculated unoccupied density of states and the spectra obtained from the impurity Anderson model. With decreasing $c$-$f$ hybridization intensity, the mid-IR peak shifts to the low-energy side owing to the renormalization of the unoccupied $4f$ state, but suddenly shifts to the high-energy side owing to the $f$-$f$ on-site Coulomb interaction at a slight localized side from the quantum critical point (QCP). This finding gives us information on the change in the electronic structure across QCP.

6 pages, 4 figures. To appear in JPSJ (Letters)

References in corpus (6)

• Quantum Criticality in Heavy Fermion Metals
• Observation of an optical non-Fermi-liquid behavior in the heavy fermion state of YbRh${}_2$Si${}_2$
• Existence of Heavy Fermions in the Antiferromagnetic Phase of CeIn3
• Origin of Middle-Infrared Peaks in Cerium Compounds
• Origin of infrared peaks in the optical conductivity of ytterbium compounds
• Far-infrared optical conductivity of CeCu2Si2

Cited by in corpus (3)

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