Unconventional Quantum Criticality due to Critical Valence Transition

Abstract

Quantum criticality due to the valence transition in some Yb-based heavy fermion metals has gradually turned out to play a crucial role to understand the non-Fermi liquid properties that cannot be understood from the conventional quantum criticality theory due to magnetic transitions. Namely, critical exponents giving the temperature (T) dependence of the resistivity ρ(T), the Sommerfeld coefficient, C(T)/T, the magnetic susceptibility, χ(T), and the NMR relaxation rates, 1/(T_{1}T), can be understood as the effect of the critical valence fluctuations of f electrons in Yb ion in a unified way. There also exist a series of Ce-based heavy fermion metals that exhibit anomalies in physical quantities, enhancements of the residual resistivity ρ_{0} and the superconducting critical temperature (T_c) around the pressure where the valence of Ce sharply changes. Here we review the present status of these problems both from experimental and theoretical aspects.

Published in "Special Topics: Advances in Physics of Strongly Correlated Electron Systems" of J. Phys. Soc. Jpn. based on an invited talk at SCES2013. Free access for one month from now through the link of J. Phys. Soc. Jpn.; http://journals.jps.jp/journal/jpsj

References in corpus (12)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Signatures of valence fluctuations in CeCu2Si2 under high pressure
• Magnetically driven superconductivity in CeCu2Si2
• Quantum critical state in a magnetic quasicrystal
• Quantum Valence Criticality as Origin of Unconventional Critical Phenomena
• The quantum critical point in CeRhIn_5: a resistivity study
• Roles of Critical Valence Fluctuations in Ce- and Yb-Based Heavy Fermion Metals
• Superconductivity emerging near quantum critical point of valence transition
• Magnetic-Field Control of Quantum Critical Points of Valence Transition
• β-YbAlB4: a critical nodal metal
• Valence Fluctuations Revealed by Magnetic Field Scan: Comparison with Experiments in YbXCu_4 (X=In, Ag, Cd) and CeYIn_5 (Y=Ir, Rh)
• New Universality Class of Quantum Criticality in Ce- and Yb-based Heavy Fermions

Cited by in corpus (11)

• Emergent loop-nodal s${}_{\pm }$-wave superconductivity in CeCu${}_2$Si${}_2$: similarities to the iron-based superconductors
• Quantum Criticality in the Ferromagnetic Superconductor UCoGe under Pressure and Magnetic Field
• T/B Scaling in beta-YbAlB4
• Quantum Criticality of Valence Transition for the Unique Electronic State of Antiferromagnetic Compound EuCu2Ge2
• Localized-to-itinerant transition preceding antiferromagnetic quantum critical point and gapless superconductivity in CeRh${}_{0.5}$Ir${}_{0.5}$In${}_5$
• Coincidence of magnetic and valence quantum critical points in CeRhIn5 under pressure
• Thermal Expansion of the Heavy-fermion Superconductor PuCoGa${}_5$
• Extended Nuclear Quadrupole Resonance Study of the Heavy-Fermion Superconductor PuCoGa${}_5$
• New Quantum Criticality Revealed under Pressure
• Pressure dependence of Ce valence in CeRhIn5
• Theory for Non-Fermi Liquid Temperature Dependence in Resistivity of Ce_xLa_{1-x} Cu_{5.62} Au_{0.38} (x=0.02-0.10) on the Local Quantum Valence Criticality of Ce Impurities