Heavy fermion superconductor CeCu<sub>2</sub>Si<sub>2</sub> under high pressure: Multiprobing the valence crossover

Seyfarth, Gabriel; Ruetschi, Anna-Sabina; Sengupta, Kausik; Georges, Antoine; Jaccard, Didier; Watanabe, S.; Miyake, K.

doi:10.1103/PhysRevB.85.205105

Scientific article

English

Heavy fermion superconductor CeCu₂Si₂ under high pressure: Multiprobing the valence crossover

Contributors

Seyfarth, Gabriel; Ruetschi, Anna-Sabina; Sengupta, Kausik; Georges, Antoine; Jaccard, Didier; Watanabe, S.; Miyake, K.

Published in

Physical review. B, Condensed matter and materials physics, vol. 85, no. 20

Publication date

2012

Abstract

The first heavy fermion superconductor CeCu2Si2 has not revealed all its striking mysteries yet. At high pressures, superconductivity is supposed to be mediated by valence fluctuations, in contrast to ambient pressure, where spin fluctuations most likely act as pairing glue. We have carried out a multiprobe (electric transport, thermopower, ac specific heat, Hall and Nernst effects) experiment up to 7 GPa on a high-quality CeCu2Si2 single crystal. For the first time, the resistivity data make it possible quantitatively to draw the valence crossover line within the p-T plane and to locate the critical end point at 4.5 ± 0.2 GPa and a slightly negative temperature. In the same pressure region, remarkable features have also been detected in the other physical properties, presumably acting as further signatures of the Ce valence crossover and the associated critical fluctuations: We observe maxima in the Hall and Nernst effects and a sign change and a strong sensitivity on magnetic field in the thermopower signal.

UNIGE affiliation entities

Faculté des sciences / Section de physique / Département de physique de la matière quantique

Citation (ISO format)

SEYFARTH, Gabriel et al. Heavy fermion superconductor CeCu₂Si₂ under high pressure: Multiprobing the valence crossover. In: Physical review. B, Condensed matter and materials physics, 2012, vol. 85, n° 20. doi: 10.1103/PhysRevB.85.205105

Article (Published version)

Identifiers

PID : unige:35703
DOI : 10.1103/PhysRevB.85.205105

Journal ISSN

1098-0121

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Heavy fermion superconductor CeCu₂Si₂ under high pressure: Multiprobing the valence crossover

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Published in

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Abstract

UNIGE affiliation entities

Citation (ISO format)

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Technical informations

Creation

First validation

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Heavy fermion superconductor CeCu2Si2 under high pressure: Multiprobing the valence crossover

Contributors

Published in

Publication date

Abstract

UNIGE affiliation entities

Citation (ISO format)

Main files (1)

Identifiers

Journal ISSN

Technical informations

Creation

First validation

Update

Status update

Last indexation

Heavy fermion superconductor CeCu₂Si₂ under high pressure: Multiprobing the valence crossover