Signatures of Valence fluctuations in CeCu2Si2 under high pressure
By A. Holmes, D. Jaccard, K. M. U. O. Geneva, Switzerland., U. Osaka, Japan.. 2003
200 citations recorded by the source corpus.
Simultaneous resistivity and ac specific heat measurements have been performed under pressure on singlecrystalline 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, Tc max . 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 Pv in this picture, while other anomalies found around Pv can be qualitatively understood using the same model
Subfields: Condensed Matter Physics, Electronic, Optical and Magnetic Materials
View Paper: https://www.semanticscholar.org/paper/185fbf071b61ff575d02adf9c3edb1fccc7d5493
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In Condensed Matter Physics
In Electronic, Optical and Magnetic Materials
Citations in the corpus
- Superconducting phases of f -electron compounds (2009, background): “Further studies established, that the T 2 coefficient of the resistivity drops abruptly, when the characteristic temperature scale Tmax1 varies under pressure or Ge-doping reaches a value of ∼ 70 K (Holmes et al., 2004).”
- Superconductivity and quantum criticality in the heavy-fermion system |[beta]|-YbAlB4 (2008, background): “Superconductivity in the cerium compounds has been variously described in terms of intersite spin–spin interactions as well as in some cases in terms of effects that arise on the border of density or valence instabilitie”
- Magnetically driven superconductivity in CeCu$_2$Si$_2$ (2011, background): “Superconductivity and antiferromagnetism in CeCu 2 Si 2 The SC in CeCu 2 Si 2 we consider is close to the AF QCP, and is to be contrasted with a second superconducting dome appearing at high pressure that is thought to be associated with a valence instability and the concomitant fluctuation”