Quantum Critical Point between Two-Channel Kondo and Fermi-Liquid Phases

Abstract

We investigate the emergence of quantum critical points near a two-channel Kondo phase by evaluating an $f$-electron entropy of a seven-orbital impurity Anderson model hybridized with three (${\Gamma }_7$ and ${\Gamma }_8$) conduction bands with the use of a numerical renormalization group method First we consider the case of Pr${}^{3+}$ ion, in which quadrupole two-channel Kondo effect is known to occur for the local ${\Gamma }_3$ doublet state. When we control crystalline electric field (CEF) potentials so as to change the local CEF ground state from ${\Gamma }_3$ doublet to ${\Gamma }_1$ singlet or ${\Gamma }_5$ triplet, we commonly observe a residual entropy of $\log \varphi$ with the golden ratio $\varphi =(1+\sqrt{5})/2$, which is equal to that for three-channel Kondo effect. This peculiar residual entropy is also observed for the case of Nd${}^{3+}$ ion, in which magnetic two-channel Kondo phase is found to occur for the local ${\Gamma }_6$ doublet state. We envisage a scenario that the quantum critical point characterized by $\log \varphi$ generally appears between two-channel Kondo and Fermi-liquid phases.

10 pages, 11 figures. To appear in J. Phys. Soc. Jpn

References in corpus (5)

• Universal low-temperature crossover in two-channel Kondo models
• Influence of lattice structure on multipole interactions in ${\Gamma }_3$ non-Kramers doublet systems
• Two-channel Kondo Effect Emerging from Nd Ions
• Kondo effect in the seven-orbital Anderson model hybridized with ${\Gamma }_8$ conduction electrons
• Two-Channel Kondo Effect Emerging from Np and Pu Ions