Signatures of valence fluctuations in CeCu2Si2 under high pressure

A.T. Holmes, D. Jaccard, K. Miyake

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314 Citations (Scopus)


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

ASJC Scopus subject areas

  • Condensed Matter Physics


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