Signatures of valence fluctuations in CeCu2Si2 under high pressure

Research output: Contribution to journalArticlepeer-review

Authors

Colleges, School and Institutes

External organisations

  • Osaka University
  • University of Geneva

Abstract

Simultaneous resistivity and ac specific heat measurements have been performed under pressure on single-crystalline CeCu2Si2 to over 6 GPa in a hydrostatic helium pressure medium. A series of anomalies was observed around the pressure coinciding with a maximum in the superconducting critical temperature, T These anomalies can be linked with an abrupt change of the Ce valence and suggest a second quantum critical point at a pressure Pv≃4.5 GPa, where critical valence fluctuations provide the superconducting pairing mechanism, as opposed to spin fluctuations at ambient pressure. Such a valence instability-and associated superconductivity-is predicted by an extended Anderson lattice model with Coulomb repulsion between the conduction and f electrons. We explain the T-linear resistivity found at P in this picture, while other anomalies found around P can be qualitatively understood using the same model.

Details

Original languageEnglish
Pages (from-to)024508
Number of pages11
JournalPhysical Review B
Volume69
Issue number2
Publication statusPublished - 15 Jan 2004

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