Hexadecapole fluctuation mechanism for s-wave heavy fermion superconductor CeCu2Si2: Interplay between intra- and inter-orbital Cooper pairs

Abstract

In heavy-fermion superconductors, it is widely believed that the superconducting gap function has sign-reversal due to the strong electron correlation. However, recently discovered fully-gapped s-wave superconductivity in CeCu2Si2 has clarified that strong attractive pairing interaction can appear even in heavy-fermion systems. To understand the origin of attractive force, we develop the multipole fluctuation theory by focusing on the inter-multipole many-body interaction called the vertex corrections. By analyzing the periodic Anderson model for CeCu2Si2, we find that hexadecapole fluctuations mediate strong attractive pairing interaction. Therefore, fully-gapped s-wave superconductivity is driven by pure on-site Coulomb repulsion, without introducing electron-phonon interactions. The present theory of superconductivity will be useful to understand rich variety of the superconducting states in heavy fermion systems.

arXiv comment7 pages, 7 figures

References in corpus (24)

• Superconducting phases of f-electron compounds
• Orbital Fluctuation Mediated Superconductivity in Iron Pnictides: Analysis of Five Orbital Hubbard-Holstein Model
• Angular Position of Nodes in the Superconducting Gap of Quasi-2D Heavy-Fermion Superconductor CeCoIn_5
• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Theory of Superconductivity in Strongly Correlated Electron Systems
• Review of U-based Ferromagnetic Superconductors: Comparison between UGe2, URhGe, and UCoGe
• Modelling the Localized to Itinerant Electronic Transition in the Heavy Fermion System CeIrIn5
• Arrested Kondo effect and hidden order in URu_2Si_2
• Self-Consistent Vertex Correction Analysis for Iron-Based Superconductors: Mechanism of Coulomb-Interaction-Driven Orbital Fluctuations
• Anomalous Transport Phenomena in Fermi Liquids with Strong Magnetic Fluctuations
• Multiband superconductivity with unexpected deficiency of nodal quasiparticles in CeCu2Si2
• Nematicity and magnetism in FeSe and other families of Fe-based superconductors
• Fully gapped superconductivity with no sign change in the prototypical heavy-fermion CeCu2Si2
• Fully gapped $d$-wave superconductivity in CeCu${}_2$Si${}_2$
• Emergent loop-nodal s${}_{\pm }$-wave superconductivity in CeCu${}_2$Si${}_2$: similarities to the iron-based superconductors
• Spin Triplet Superconductivity in Sr2RuO4 due to Orbital and Spin Fluctuations: Analysis by Two-Dimensional Renormalization Group Theory
• Spin-triplet superconductivity in Sr2RuO4 due to orbital and spin fluctuations: Analyses by two-dimensional renormalization group theory and self-consistent vertex-correction method
• Theoretical prediction and spectroscopic fingerprints of an orbital transition in CeCu2Si2
• Meta-orbital Transition in Heavy-fermion Systems: Analysis by Dynamical Mean Field Theory and Self-consistent Renormalization Theory of Orbital Fluctuations
• Thermodynamic study of gap structure and pair-breaking effect by magnetic field in the heavy-fermion superconductor CeCu2Si2
• Functional renormalization group study of orbital fluctuation mediated superconductivity: Impact of the electron-boson coupling vertex corrections
• Fully gapped s-wave superconductivity enhanced by magnetic criticality in heavy fermion system
• Plain $s$-wave superconductivity near the magnetic criticality: Enhancement of attractive electron-boson coupling vertex corrections
• Superconductivity in the Orbital Degenerate Model for Heavy Fermion Systems

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• Novel attractive pairing interaction in strongly correlated superconductors
• Classification of multiorbital superconducting state based on augmented multipoles
• Unified mechanism of charge-density-wave and high-$T_c$ superconductivity protected from oxygen vacancies in bilayer nickelates
• Robust $T$-Linear Resistivity due to SU(4) Valley + Spin Fluctuation Mechanism in Magic Angle Twisted Bilayer Graphene
• Removal of excess iron by annealing processes and emergence of bulk superconductivity in sulfur-substituted FeTe