Gap symmetry of the heavy fermion superconductor CeCu${}_2$Si${}_2$ at ambient pressure

Abstract

Recent observations of two nodeless gaps in superconducting CeCu${}_2$Si${}_2$ have raised intensive debates on its exact gap symmetry, while a satisfactory theoretical basis is still lacking. Here we propose a phenomenological approach to calculate the superconducting gap functions, taking into consideration both the realistic Fermi surface topology and the intra- and interband quantum critical scatterings. Our calculations yield a nodeless $s^{\pm }$-wave solution in the presence of strong interband pairing interaction, in good agreement with experiments. This provides a possible basis for understanding the superconducting gap symmetry of CeCu${}_2$Si${}_2$ at ambient pressure and indicates the potential importance of multiple Fermi surfaces and interband pairing interaction in understanding heavy fermion superconductivity.

7 pages, 5 figures

References in corpus (14)

• Near-degeneracy of several pairing channels in multiorbital models for the Fe-pnictides
• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Magnetically driven superconductivity in CeCu2Si2
• Feedback spin resonance in superconducting CeCu${}_2$Si${}_2$ and CeCoIn${}_5$
• Interband superconductivity: contrasts between BCS and Eliashberg theory
• Orbital selective pairing and superconductivity in iron selenides
• Fully gapped superconductivity with no sign change in the prototypical heavy-fermion CeCu2Si2
• Superconducting Properties of the $s^{\pm }$-wave state: Fe-based superconductors
• Emergent loop-nodal s${}_{\pm }$-wave superconductivity in CeCu${}_2$Si${}_2$: similarities to the iron-based superconductors
• Full-gap superconductivity robust against disorder in heavy-fermion CeCu2Si2
• Unconventional Quantum Criticality due to Critical Valence Transition
• Thermodynamic study of gap structure and pair-breaking effect by magnetic field in the heavy-fermion superconductor CeCu2Si2
• The Emergence of Superconductivity in Heavy Electron Materials
• Magnetic and superconducting properties on S-type single-crystal CeCu${}_2$Si${}_2$ probed by ${}^{63}$Cu nuclear magnetic resonance and nuclear quadrupole resonance

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• Revealing the Heavy Quasiparticles in the Heavy-Fermion Superconductor CeCu2Si2
• Protracted Kondo screening and kagome bands in heavy-fermion metal Ce${}_3$Al
• Unconventional fully-gapped superconductivity in the heavy-fermion metal CeCu${}_2$Si${}_2$
• Nature of the spin resonance mode in CeCoIn${}_5$
• Interplay between unconventional superconductivity and heavy-fermion quantum criticality: CeCu${}_2$Si${}_2$ versus YbRh${}_2$Si${}_2$
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• Multipole-fluctuation pairing mechanism of $d_{x^2-y^2}+ig$ superconductivity in Sr${}_2$RuO${}_4$
• High-energy magnetic excitations from heavy quasiparticles in CeCu${}_2$Si${}_2$
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• A Simple Solvable Model for Heavy Fermion Superconductivity from the Two-Fluid Normal State
• An emerging global picture of heavy fermion physics
• Observation of two critical points linked to the high field phase B in CeCu2Si2
• Interplay between charge, magnetic and superconducting order in a Kondo lattice with an attractive Hubbard interaction
• Novel attractive pairing interaction in strongly correlated superconductors
• Revealing sign-reversal $s^{+-}$-wave pairing by quasiparticle interference in the heavy-fermion superconductor CeCu${}_2$Si${}_2$
• CeCu${}_2$Si${}_2$ and YbRh${}_2$Si${}_2$: Strange Cases of Heavy-Fermion Superconductivity
• Anomalous impurity effect in the heavy-fermion superconductor CeCu2Si2
• First-Principles Study of the Fermi Surface Topology of CeCu${}_2$Si${}_2$