Competition between Quadrupole and Magnetic Kondo Effects in Non-Kramers Doublet Systems

Abstract

We discuss possible competition between magnetic and quadrupole Kondo effects in non-Kramers doublet systems under cubic symmetry. The quadrupole Kondo effect leads to non-Fermi-liquid (NFL) ground state, while the magnetic one favors ordinary Fermi liquid (FL). In terms of the $j$-$j$ coupling scheme, we emphasize that the orbital fluctuation must develop in the vicinity of the NFL-FL boundary. We demonstrate a change of behavior in the f-electron entropy by the Wilson's numerical renormalization-group (NRG) method on the basis of the extended two-channel Kondo exchange model. We present implications to extensively investigated PrT${}_2$X${}_{20}$ (T=Ti, V, Ir; X=Al, Zn) systems that exhibit both quadrupole ordering and peculiar superconductivity. We also discuss the magnetic-field effect which lifts weakly the non-Kramers degeneracy. Our model also represents the FL state accompanied by a free magnetic spin as a consequence of stronger competition between the magnetic and the quadrupole Kondo effects.

arXiv comment10 pages, 5 figures, SCES2014 conference proceedings

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Cited by in corpus (7)

• Quadrupole-Driven Non-Fermi Liquid and Magnetic-Field Induced Heavy Fermion States in a Non-Kramers Doublet System
• Non-Fermi Liquid and Fermi Liquid in Two-Channel Anderson Lattice Model: Theory for Pr$A_2$Al${}_{20}$ ($A$=V, Ti) and PrIr${}_2$Zn${}_{20}$
• Anisotropic B-T Phase Diagram of Non-Kramers System PrRh2Zn20
• Classical Monte Carlo study for antiferro quadrupole orders in a diamond lattice
• Competing Kondo Effects in Non-Kramers Doublet Systems
• Unified description of resistivity and thermopower of Pr${}_2$Ir${}_2$O${}_7$: possible influence of crystal field excitation in a Kondo lattice
• Thermal and field-induced transitions in ferroquadrupolar Kondo systems