Magnetically driven superconductivity in CeCu2Si2

Abstract

The origin of unconventional superconductivity, including high-temperature and heavy-fermion superconductivity, is still a matter of controversy. Spin excitations instead of phonons are thought to be responsible for the formation of Cooper pairs. Using inelastic neutron scattering, we present the first in-depth study of the magnetic excitation spectrum in momentum and energy space in the superconducting and the normal states of CeCu2Si2. A clear spin excitation gap is observed in the superconducting state. We determine a lowering of the magnetic exchange energy in the superconducting state, in an amount considerably larger than the superconducting condensation energy. Our findings identify the antiferromagnetic excitations as the major driving force for superconducting pairing in this prototypical heavy-fermion compound located near an antiferromagnetic quantum critical point.

30 pages, including supplementary material

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Cited by in corpus (30)

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• Pressure induced superconductivity on the border of magnetic order in MnP
• Quantum and classical criticality in a dimerized quantum antiferromagnet
• Disorder in a Quantum Critical Superconductor
• Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions
• Emergent loop-nodal s${}_{\pm }$-wave superconductivity in CeCu${}_2$Si${}_2$: similarities to the iron-based superconductors
• Superconductivity in Ce- and U-based "122" heavy-fermion compounds
• Direct Evidence for a Magnetic f-electron Mediated Cooper Pairing Mechanism of Heavy Fermion Superconductivity in CeCoIn5
• Unconventional Superconductivity from Local Spin Fluctuations in the Kondo Lattice
• Unconventional Quantum Criticality due to Critical Valence Transition
• The magnitude of the magnetic exchange interaction in the heavy fermion antiferromagnet CeRhIn${}_5$
• Robust Upward Dispersion of the Neutron Spin Resonance in the Heavy Fermion Superconductor Ce${}_{1-x}$Yb${}_x$CoIn${}_5$
• Hall effect in heavy-fermion metals
• Europium mixed-valence, long-range magnetic order, and dynamic magnetic response in EuCu${}_2$(Si${}_x$Ge${}_{1-x}$)${}_2$
• Thermodynamic study of gap structure and pair-breaking effect by magnetic field in the heavy-fermion superconductor CeCu2Si2
• Field-induced quantum fluctuations in the heavy fermion superconductor CeCu2Ge2
• Physical properties and magnetic structure of the intermetallic CeCuBi2 compound
• Spin Exciton Formation inside the Hidden Order Phase of CeB6
• Structural investigations of CeIrIn${}_5$ and CeCoIn${}_5$ on macroscopic and atomic length scales
• Theory of Scanning Tunneling Spectroscopy: from Kondo Impurities to Heavy Fermion Materials
• D-wave superconductivity induced by short-range antiferromagnetic correlations in the two-dimensional Kondo lattice model
• Field induced spin exciton doublet splitting in d_{x^2-y^2}-wave 115-heavy electron superconductors
• Momentum-space structure of quasielastic spin fluctuations in Ce3Pd20Si6
• Magnetic-field and doping dependence of low-energy spin fluctuations in the antiferroquadrupolar compound Ce(1-x)La(x)B(6)
• CeCu_2Ge_2: Challenging our Understanding of Quantum Criticality
• Giant overlap between the magnetic and superconducting phases of CeAu2Si2 under pressure
• Kondo lattice heavy fermion behavior in CeRh2Ga2
• Cluster Extended Dynamical Mean Field Approach and Unconventional Superconductivity
• Effect of disorder on the pressure-induced superconducting state of CeAu2Si2
• High pressure investigation of superconducting signatures in CeCu${}_2$Si${}_2$ : ac- magnetic susceptibility and heat capacity, resistivity and thermopower