Magnetic Field Effect on Crossover Temperature from Non-Fermi Liquid to Fermi Liquid Behavior in f2-Impurity Systems with Crystalline-Electric-Field Singlet State Competing with Kondo--Yosida Singlet State
Abstract
We investigate the magnetic field dependence of the physical properties of f2-configuration systems with a crystalline-electric field (CEF) singlet ground state, which gives rise to a non-Fermi liquid (NFL) fixed point due to the competition between the Kondo--Yosida singlet and CEF singlet states. On the basis of the numerical renormalization group method, we find that the magnetic field breaks this NFL fixed point via two mechanisms: one causing the polarization of f-electrons and the other giving the ``channel'' anisotropy. These two mechanisms induce a difference in the magnetic field dependence of the characteristic temperature TF*(H), the crossover temperature from NFL to Fermi-liquid behavior. While the polarization of f-electrons gives TF*(H) \propto Hx (x ≃ 2.0), the ``channel'' anisotropy gives the H-independent TF*(H). These two mechanisms cross over continuously at approximately the crossover magnetic field Hc, where an anomalous H-dependence of TF*(H) appears. Such TF*(H) well reproduces the NFL behaviors observed in Th1-xUxRu2Si2. We also find that the H-dependence of the resistivity and the magnetic susceptibility are in good agreement with the experimental results of this material. These results suggest that the NFL behaviors observed in Th1-xUxRu2Si2 can be understood if this material is located in the CEF singlet side near the critical phase boundary between the two singlet states.
- Publication:
-
Journal of the Physical Society of Japan
- Pub Date:
- December 2011
- DOI:
- 10.1143/JPSJ.80.124706
- arXiv:
- arXiv:1111.4718
- Bibcode:
- 2011JPSJ...80l4706N
- Keywords:
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- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 8 pages, 8figures