Theory of crystalline electric field and Kondo effect in Pr skutterudites

Junya Otsuki, Hiroaki Kusunose, Yoshio Kuramoto

Research output: Contribution to journalArticlepeer-review

51 Citations (Scopus)

Abstract

Possible Kondo effect in Pr skutterudite is studied with attention to characteristic features of low-lying crystalline electric field (CEF) levels and the conduction band. A mechanism for the small CEF splitting between a singlet and a triplet is proposed as combination of the point-charge interaction and hybridization of 4f with ligand p states. Provided 4f 3 configurations dominate over 4f 1 as intermediate states, p-f hybridization favors the triplet, while point-charge interaction favors the singlet. For realistic parameters for hybridization as well as 4f 1 and 4f 3 levels, these singlet and triplet can form a nearly degenerate pseudo-quartet. It is found that one of two spin 1/2 objects composing the pseudo-quartet has a ferromagnetic exchange, while the other has an antiferromagnetic exchange with conduction electrons. The magnitude of each effective exchange depends strongly on a parameter characterizing the triplet wave function under the T h symmetry. It is argued that differences of this parameter among Pr skutterdudites are responsible for the apparent diversity of their physical properties. Numerical renormalization group is used to derive the renormalization flows going toward singlet, doublet, triplet or quaret according to the CEF splitting and exchange interactions.

Original languageEnglish
Pages (from-to)200-208
Number of pages9
Journaljournal of the physical society of japan
Volume74
Issue number1
DOIs
Publication statusPublished - Jan 2005

Keywords

  • Crystalline electric field
  • Filled skutterudite
  • Hybridization
  • Kondo effect
  • PrFe P
  • PrOs Sb

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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