Superconducting gap and vortex lattice of the heavy fermion compound CeCu_2Si_2

Abstract

The order parameter and pairing mechanism for superconductivity in heavy fermion compounds are still poorly understood. Scanning tunneling microscopy and spectroscopy at ultra-low temperatures can yield important information about the superconducting order parameter and the gap structure. Here, we study the first heavy fermion superconductor, CeCu_2Si_2. Our data show the superconducting gap which is not fully formed and exhibits features that point to a multi-gap order parameter. Spatial mapping of the zero bias conductance in magnetic field reveals the vortex lattice, which allows us to unequivocally link the observed conductance gap to superconductivity in CeCu_2Si_2. The vortex lattice is found to be predominantly triangular with distortions at fields close to \sim 0.7 H_{c2}.

6 pages, 4 figures, revised version accepted for publication in PRB

References in corpus (8)

• Imaging the Fano Lattice to 'Hidden Order' Transition in URu2Si2
• Magnetically driven superconductivity in CeCu2Si2
• Visualizing heavy fermions emerging in a quantum critical Kondo lattice
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• High Resolution Photoemission Study on Low-T_K Ce Systems: Kondo Resonance, Crystal Field Structures, and their Temperature Dependence
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• Revealing the Heavy Quasiparticles in the Heavy-Fermion Superconductor CeCu2Si2
• Thermodynamic study of gap structure and pair-breaking effect by magnetic field in the heavy-fermion superconductor CeCu2Si2
• Unconventional fully-gapped superconductivity in the heavy-fermion metal CeCu${}_2$Si${}_2$
• Feedback of superconductivity on the magnetic excitation spectrum of UTe${}_2$
• Theory of Scanning Tunneling Spectroscopy: from Kondo Impurities to Heavy Fermion Materials
• Interplay between unconventional superconductivity and heavy-fermion quantum criticality: CeCu${}_2$Si${}_2$ versus YbRh${}_2$Si${}_2$
• In Situ STM Observation of Nonmagnetic Impurity Effect in MBE-grown CeCoIn${}_5$ Films
• Possible nodeless $s^{\pm }$-wave superconductivity in twisted bilayer graphene
• Variational cluster approach to superconductivity and magnetism in the Kondo lattice model
• Microscopic Eilenberger theory of Fulde-Ferrell-Larkin-Ovchinnikov states in the presence of vortices
• Low frequency Raman study of the Boson peak in a Tellurite-tungstate glass over temperature
• 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${}_2$
• Anomalous impurity effect in the heavy-fermion superconductor CeCu2Si2