title: Direct evidence for a magnetic f-electron-mediated pairing mechanism of heavy-fermion superconductivity in CeCoIn5.
abstract: To identify the microscopic mechanism of heavy-fermion Cooper pairing is an unresolved challenge in quantum matter studies; it may also relate closely to finding the pairing mechanism of high-temperature superconductivity. Magnetically mediated Cooper pairing has long been the conjectured basis of heavy-fermion superconductivity but no direct verification of this hypothesis was achievable. Here, we use a novel approach based on precision measurements of the heavy-fermion band structure using quasiparticle interference imaging to reveal quantitatively the momentum space (k-space) structure of the f-electron magnetic interactions of CeCoIn5. Then, by solving the superconducting gap equations on the two heavy-fermion bands Ek(α,β) with these magnetic interactions as mediators of the Cooper pairing, we derive a series of quantitative predictions about the superconductive state. The agreement found between these diverse predictions and the measured characteristics of superconducting CeCoIn5 then provides direct evidence that the heavy-fermion Cooper pairing is indeed mediated by f-electron magnetism.
authors: Department of Physics, University of Illinois at Chicago, Chicago, IL 60607;
authors: John S
authors: JS
authors: Van Dyke
authors: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;
authors: Freek
authors: F
authors: Massee
authors: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;Department of Physics, Eidgenössische Technische Hochschule Zürich, CH-8093 Zurich, Switzerland;
authors: Milan P
authors: MP
authors: Allan
authors: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University, Ithaca, NY 14853;School of Physics and Astronomy, University of St. Andrews, Fife KY16 9SS, United Kingdom; andKavli Institute at Cornell, Cornell University, Ithaca, NY 14853 jcseamusdavis@gmail.com dkmorr@uic.edu.
authors: J C Séamus
authors: JC
authors: Davis
authors: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973;
authors: Cedomir
authors: C
authors: Petrovic
authors: Department of Physics, University of Illinois at Chicago, Chicago, IL 60607; jcseamusdavis@gmail.com dkmorr@uic.edu.
authors: Dirk K
authors: DK
authors: Morr
keywords: f-electron–mediated pairing mechanism; heavy fermion materials; unconventional superconductivity