Revealing the Heavy Quasiparticles in the Heavy-Fermion Superconductor CeCu2Si2

Abstract

The superconducting order parameter of the first heavy-fermion superconductor CeCu2Si2 is currently under debate. A key ingredient to understand its superconductivity and physical properties is the quasiparticle dispersion and Fermi surface, which remains elusive experimentally. Here we present measurements from angle-resolved photoemission spectroscopy. Our results emphasize the key role played by the Ce 4f electrons for the low-temperature Fermi surface, highlighting a band-dependent conduction-f electron hybridization. In particular, we find a very heavy quasi-two-dimensional electron band near the bulk X point and moderately heavy three-dimensional hole pockets near the Z point. Comparison with theoretical calculations reveals the strong local correlation in this compound, calling for further theoretical studies. Our results provide the electronic basis to understand the heavy fermion behavior and superconductivity; implications for the enigmatic superconductivity of this compound are also discussed.

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Cited by in corpus (16)

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• Exploring Fermi Surface Nesting and the Nature of Heavy Quasiparticles in the Spin-Triplet Superconductor Candidate CeRh${}_2$As${}_2$
• ARPES signature of the competition between magnetic order and Kondo effect in CeCoGe3
• First-principles method justifying the Dieke diagram and beyond
• Collapse of quasiparticle multiplets and $5f$ itinerant-localized crossovers in cubic phase Pu${}_3$Ga
• Proximity effect of time-reversal symmetry broken non-centrosymmetric superconductors
• An emerging global picture of heavy fermion physics
• Revealing sign-reversal $s^{+-}$-wave pairing by quasiparticle interference in the heavy-fermion superconductor CeCu${}_2$Si${}_2$
• Flat Band Generation through Interlayer Geometric Frustration in Intercalated Transition Metal Dichalcogenides
• Nesting-driven antiferromagnetic order in Kondo lattice CePd5Al2
• Correlation-driven 3d Heavy Fermion behavior in LiV2O4
• 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${}_2$