Valence Instability and Superconductivity in Heavy Fermion Systems

Abstract

Many cerium-based heavy fermion (HF) compounds have pressure-temperature phase diagrams in which a superconducting region extends far from a magnetic quantum critical point. In at least two compounds, CeCu2Si2 and CeCu2Ge2, an enhancement of the superconducting transition temperature was found to coincide with an abrupt valence change, with strong circumstantial evidence for pairing mediated by critical valence, or charge transfer, fluctuations. This pairing mechanism, and the valence instability, is a consequence of a f-c Coulomb repulsion term U_fc in the hamiltonian. While some non-superconducting Ce compounds show a clear first order valence instability, analogous to the Ce alpha-gamma transition, we argue that a weakly first order valence transition may be a general feature of Ce-based HF systems, and both magnetic and critical valence fluctuations may be responsible for the superconductivity in these systems.

11 pages, 16 figures

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• Superconductivity and Quantum Criticality in CeCoIn_5
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• p-wave and d-wave superconductivity in quasi-two-dimensional metals
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Cited by in corpus (34)

• The quantum critical point in CeRhIn_5: a resistivity study
• Emergent loop-nodal s${}_{\pm }$-wave superconductivity in CeCu${}_2$Si${}_2$: similarities to the iron-based superconductors
• Unified understanding of the valence transition in the rare-earth monochalcogenides under pressure
• Superconductivity in Ce- and U-based "122" heavy-fermion compounds
• Theoretical prediction and spectroscopic fingerprints of an orbital transition in CeCu2Si2
• Unconventional Superconductivity from Local Spin Fluctuations in the Kondo Lattice
• Evidence for a charge collective mode associated with superconductivity in copper oxides from neutron and x-ray scattering measurements of La${}_{2-x}$Sr${}_x$CuO${}_4$
• Thermal conductivity evidence for d_{x^2-y^2} pairing symmetry in the heavy-fermion CeIrIn5 superconductor
• Kondo destruction and valence fluctuations in an Anderson model
• Heavy Fermion superconductor CeCu${}_2$Si${}_2$ under high pressure: multiprobing the valence crossover
• Magneto-transport properties governed by the antiferromagnetic fluctuations in heavy fermion superconductor CeIrIn${}_5$
• Valence Instability of YbCu${}_2$Si${}_2$ through its quantum critical point
• A precursor state to unconventional superconductivity in CeIrIn${}_5$
• Correlation-driven multigap d-wave superconductivity in Anderson lattice model
• The Dominant Role of Critical Valence Fluctuations on High $T_{\mathrm{c}}$ Superconductivity in Heavy Fermions
• Possible multi-orbital ground state in CeCu${}_2$Si${}_2$
• Electronic and magnetic properties of superconducting LnO${}_{1-x}$F${}_x$BiS${}_2$ (Ln = La, Ce, Pr, and Nd) from first principles
• Superconducting gap structure of CeIrIn5 from field-angle-resolved measurements of its specific heat
• Novel Valence Transition in Elemental Metal Europium around 80 GPa
• Quantum criticality and first-order transitions in the extended periodic Anderson model
• Anomalous connection between antiferromagnetic and superconducting phases in pressurized non-centrosymmetric heavy fermion compound CeRhGe3
• Study of photoinduced valence dynamics in EuNi${}_2$(Si${}_{0.21}$Ge${}_{0.79}$)${}_2$ through time-resolved X-ray absorption spectroscopy
• Quantum normal-to-inhomogeneous superconductor phase transition in nearly two-dimensional metals
• Heavy-Fermion Superconductivity in CeAg${}_2$Si${}_2$ --Interplay of Spin and Valence Fluctuations--
• Effect of disorder on the pressure-induced superconducting state of CeAu2Si2
• Charge fluctuations in the intermediate-valence ground state of SmCoIn${}_5$
• High-pressure study of the ground- and superconducting-state properties of CeAu${}_2$Si${}_2$
• High pressure investigation of superconducting signatures in CeCu${}_2$Si${}_2$ : ac- magnetic susceptibility and heat capacity, resistivity and thermopower
• Pressure dependence of the magnetic ground state in CePtSi2
• Pressure dependence of Ce valence in CeRhIn5
• Electronic Landscape of Ce-based Intermetallics: CeCu${}_2$Si${}_2$ at an Extreme
• Momentum distribution functions in a one-dimensional extended periodic Anderson model
• Superconductivity from a non-Fermi liquid metal : Kondo fluctuation mechanism in the slave-fermion theory
• Introduction to High-Temperature Superconductivity for Solid State Chemists