Anisotropy, disorder, and superconductivity in CeCu2Si2 under high pressure

Abstract

Resistivity measurements were carried out up to 8 GPa on single crystal and polycrystalline samples of CeCu2Si2 from differing sources in the homogeneity range. The anisotropic response to current direction and small uniaxial stresses was explored, taking advantage of the quasi-hydrostatic environment of the Bridgman anvil cell. It was found that both the superconducting transition temperature Tc and the normal state properties are very sensitive to uniaxial stress, which leads to a shift of the valence instability pressure Pv and a small but significant change in Tc for different orientations with respect to the tetragonal c-axis. Coexistence of superconductivity and residual resistivity close to the Ioffe-Regel limit around 5 GPa provides a compelling argument for the existence of a valence-fluctuation mediated pairing interaction at high pressure in CeCu2Si2.

arXiv comment12 pages, 7 figures

References in corpus (6)

• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Enhanced Valence Fluctuations Caused by f-c Coulomb Interaction in Ce-Based Heavy Electrons: Possible Origin of Pressure-Induced Enhancement of Superconducting Transition Temperature in \Ge and Related Compounds
• Huge Enhancement of Impurity Scattering due to Critical Valence Fluctuations in a Ce-Based Heavy Electron System
• Enhanced Impurity Scattering due to Quantum Critical Fluctuations
• Density Fluctuation Mediated Superconductivity
• Strain enhancement of superconductivity in CePd2Si2 under pressure

Cited by in corpus (6)

• Heavy Fermion superconductor CeCu${}_2$Si${}_2$ under high pressure: multiprobing the valence crossover
• The Dominant Role of Critical Valence Fluctuations on High $T_{\mathrm{c}}$ Superconductivity in Heavy Fermions
• Valence fluctuation mediated superconductivity in CeCu2Si2
• Effect of disorder on the pressure-induced superconducting state of CeAu2Si2
• High-pressure study of the ground- and superconducting-state properties of CeAu${}_2$Si${}_2$
• High pressure investigation of superconducting signatures in CeCu${}_2$Si${}_2$ : ac- magnetic susceptibility and heat capacity, resistivity and thermopower