Roles of Critical Valence Fluctuations in Ce- and Yb-Based Heavy Fermion Metals

Abstract

The roles of critical valence fluctuations of Ce and Yb are discussed as a key origin of several anomalies observed in Ce- and Yb-based heavy fermion systems. Recent development of the theory has revealed that a magnetic field is an efficient control parameter to induce the critical end point of the first-order valence transition. Metamagnetism and non-Fermi liquid behavior caused by this mechanism are discussed by comparing favorably with CeIrIn5, YbAgCu4, and YbIr2Zn20. The interplay of the magnetic order and valence fluctuations offers a key concept for understanding Ce- and Yb-based systems. It is shown that suppression of the magnetic order by enhanced valence fluctuations gives rise to the coincidence of the magnetic-transition point and valence-crossover point at absolute zero as a function of pressure or magnetic field. The interplay is shown to resolve the outstanding puzzle in CeRhIn5 in a unified way. The broader applicability of this newly clarified mechanism is discussed by surveying promising materials such as YbAuCu4, beta-YbAlB4, and YbRh2Si2.

17 pages, 8 figures, invited paper in special issue on strongly correlated electron systems

References in corpus (13)

• Quantum Criticality in Heavy Fermion Metals
• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Multiple energy scales at a quantum critical point
• Reversible Tuning of the Heavy Fermion Ground State in CeCoIn${}_5$
• Quantum Valence Criticality as Origin of Unconventional Critical Phenomena
• The quantum critical point in CeRhIn_5: a resistivity study
• Superconductivity emerging near quantum critical point of valence transition
• Magnetic-Field Control of Quantum Critical Points of Valence Transition
• Valence Fluctuations Revealed by Magnetic Field Scan: Comparison with Experiments in YbXCu_4 (X=In, Ag, Cd) and CeYIn_5 (Y=Ir, Rh)
• Violation of critical universality at the antiferromagnetic phase transition of YbRh2Si2
• Strong Coupling between Antiferromagnetic and Superconducting Order Parameters in CeRhIn${}_5$ Studied by In-NQR Spectroscopy
• Pressure-induced change of the pairing symmetry in superconducting CeCu2Si2
• Enhancement of Nuclear Spin-Lattice Relaxation Rate and Spin Susceptibility due to Valence Fluctuations -Origin of Anomalously Enhanced Wilson Ratio in Ce and Yb Systems-

Cited by in corpus (22)

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• Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions
• Pressure-Induced Valence Crossover and Novel Metamagnetic Behavior near the Antiferromagnetic Quantum Phase Transition of YbNi${}_3$Ga${}_9$
• Unconventional Quantum Criticality due to Critical Valence Transition
• New Universality Class of Quantum Criticality in Ce- and Yb-based Heavy Fermions
• Three-dimensional critical phase diagram of the Ising antiferromagnet CeRh${}_2$Si${}_2$ under intense magnetic field and pressure
• Quantum Criticality of Valence Transition for the Unique Electronic State of Antiferromagnetic Compound EuCu2Ge2
• Tuning the parity of superconductivity in CeRh2As2 via pressure
• Novel Valence Transition in Elemental Metal Europium around 80 GPa
• Strong pressure dependence of the magnetic penetration depth in single crystals of the heavy fermion superconductor CeCoIn5 studied by muon spin rotation
• Charge Transfer Effect under Odd-Parity Crystalline Electric Field: Divergence of Magnetic Toroidal Fluctuation in $\beta$-YbAlB${}_4$
• Giant spectral renormalization and complex hybridization physics in a Kondo lattice system, CeCuSb2
• Coincidence of magnetic and valence quantum critical points in CeRhIn5 under pressure
• Pressure study on the interplay between magnetic order and valence-change crossover in EuPd${}_2$(Si${}_{1-x}$Ge${}_x$)${}_2$
• Theory of Charge Order and Heavy-Electron Formation in the Mixed-Valence Compound KNi${}_2$Se${}_2$
• Heavy-Fermion Superconductivity in CeAg${}_2$Si${}_2$ --Interplay of Spin and Valence Fluctuations--
• Variation of Pressure-Induced Valence Transition with Approximation Degree in Yb-Based Quasicrystalline Approximants
• Wide Quantum Critical Region of Valence Fluctuations: Origin of Robust Quantum Criticality in Quasicrystal Yb15Al34Au51 under Pressure
• New Quantum Criticality Revealed under Pressure
• Pressure dependence of the magnetic ground state in CePtSi2
• Pressure dependence of Ce valence in CeRhIn5
• Magnetic structure and crystal field states of antiferromagnetic CeNiGe${}_3$: Neutron scattering and $\mu$SR investigations