title: Can Competition between the crystal field and the Kondo effect cause non-Fermi-liquid-like behavior?
abstract: The recently reported unusual behavior of the static and dynamical magnetic susceptibility as well as the specific heat in Ce(1-x)La(x)Ni9Ge4 has raised the question of a possible non-Fermi-liquid ground state in this material. We argue that for a consistent physical picture the crystal-field splitting of two low-lying magnetic doublets of the Ce 4f-shell must be taken into account. Furthermore, we show that for a splitting of the order of the low temperature scale T* of the system a crossover behavior between an SU(4) and an SU(2) Kondo effect is found. The screening of the two doublets occurs on different temperature scales leading to a different behavior of the magnetic susceptibility and the specific heat at low temperatures. The experimentally accessible temperature regime down to 50 mK still lies in the extended crossover regime into a strong-coupling Fermi-liquid fixed point.
authors.affiliation: Theoretical Physics, University of the Saarland, 66041 Saarbrücken, Germany.
authors.forename: Frithjof B
authors.initials: FB
authors.lastname: Anders
authors.forename: Thomas
authors.initials: T
authors.lastname: Pruschke