Issue |
EPL
Volume 98, Number 1, April 2012
|
|
---|---|---|
Article Number | 17012 | |
Number of page(s) | 6 | |
Section | Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties | |
DOI | https://doi.org/10.1209/0295-5075/98/17012 | |
Published online | 12 April 2012 |
Proximity to valence transition in heavy fermion superconductor CeCu2Si2 under pressure
1
DPMC - Université de Genève - Quai Ernest Ansermet 24, 1211 Geneva 4, Switzerland
2
Centre de Physique Théorique, École Polytechnique, CNRS - 91128 Palaiseau Cedex, France, EU
3
Collège de France - 11 place Marcelin Berthelot, 75005 Paris, France, EU
Received:
29
January
2012
Accepted:
14
March
2012
The first heavy fermion superconductor CeCu2Si2 is still only partially understood. At high pressures, superconductivity is supposed to be mediated by a different mechanism than at ambient pressure, where spin fluctuations most likely act as pairing glue. We have obtained and analyzed new resistivity data up to 7 GPa on a good quality CeCu2Si2 single crystal with an unprecedented high transition temperature. For the first time, we establish quantitatively that CeCu2Si2 lies in proximity to a valence transition: the critical end point could be located at 4.5±0.2 GPa and a slightly negative temperature, and the corresponding valence cross-over line has been added to the p-T phase diagram. This outcome is essential for the theoretically predicted critical valence fluctuations scenario, and opens new routes for further investigations in other Ce-based compounds.
PACS: 75.20.Hr – Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions / 74.62.Fj – Effects of pressure / 74.25.fc – Electric and thermal conductivity
© EPLA, 2012
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