Giant overlap between the magnetic and superconducting phases of CeAu2Si2 under pressure
arXiv:1406.1438
Abstract
High pressure provides a powerful means for exploring unconventional superconductivity which appears mostly on the border of magnetism. Here we report the discovery of pressure-induced heavy fermion superconductivity up to 2.5 K in the antiferromanget CeAu2Si2 (TN ~ 10 K). Remarkably, the magnetic and superconducting phases are found to overlap across an unprecedentedly wide pressure interval from 11.8 to 22.3 GPa. Moreover, both the bulk Tc and TM are strongly enhanced when increasing the pressure from 16.7 to 20.2 GPa. Tc reaches a maximum at a pressure slightly below pc ~ 22.5 GPa, at which magnetic order disappears. Furthermore, the scaling behavior of the resistivity provides evidence for a continuous delocalization of the Ce 4f-electrons associated with a critical endpoint lying just above pc. We show that the maximum Tc of CeAu2Si2 actually occurs at almost the same unit-cell volume as that of CeCu2Si2 and CeCu2Ge2, and when the Kondo and crystal field splitting energies becomes comparable. Dynamical mean-filed theory calculations suggest that the peculiar behavior in pressurized CeAu2Si2 might be related to its Ce 4f-orbital occupancy. Our results not only provide a unique example of the interplay between superconductivity and magnetism, but also underline the role of orbital physics in understanding Ce-based heavy fermion systems.
arXiv comment10 pages, 4 figures. Supplemental Material available on request
References in corpus (13)
- Continuous-time Monte Carlo methods for quantum impurity models
- Dynamical Mean-Field Theory within an Augmented Plane-Wave Framework: Assessing Electronic Correlations in the Iron Pnictide LaFeAsO
- Signatures of valence fluctuations in CeCu2Si2 under high pressure
- Magnetically driven superconductivity in CeCu2Si2
- Importance of electronic correlations for structural and magnetic properties of the iron pnictide superconductor LaFeAsO
- Multiband superconductivity with unexpected deficiency of nodal quasiparticles in CeCu2Si2
- Novel Pressure Phase Diagram of Heavy Fermion Superconductor CePtSi Investigated by ac Calorimetry
- Theoretical prediction and spectroscopic fingerprints of an orbital transition in CeCu2Si2
- Antiferromagnetism and Superconductivity in Cerium based Heavy Fermion Compounds
- Heavy Fermion superconductor CeCuSi under high pressure: multiprobing the valence crossover
- Meta-orbital Transition in Heavy-fermion Systems: Analysis by Dynamical Mean Field Theory and Self-consistent Renormalization Theory of Orbital Fluctuations
- Composite pairing in a mixed valent two channel Anderson model
- Calorimetric and transport investigations of CePd_{2+x}Ge_{2-x} (x=0 and 0.02) up to 22 GPa