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.
Original language | English |
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Pages (from-to) | 024508 |
Number of pages | 11 |
Journal | Physical Review B |
Volume | 69 |
Issue number | 2 |
DOIs | |
Publication status | Published - 15 Jan 2004 |
ASJC Scopus subject areas
- Condensed Matter Physics