Unusual Non-Fermi Liquid Behavior of Ce$_{1-x}$La$_{x}$Ni$_{9}$Ge$_4$ Analyzed in a Single Impurity Anderson Model with Crystal Field Effects

E. -W. Scheidt; F. Mayr; U. Killer; W. Scherer; H. Michor; E. Bauer; S. Kehrein; Th. Pruschke; F. Anders

doi:10.1016/j.physb.2006.01.263

paper

Unusual Non-Fermi Liquid Behavior of Ce $_{1 - x}$ La $_{x}$ Ni $_{9}$ Ge $_{4}$ Analyzed in a Single Impurity Anderson Model with Crystal Field Effects

arXiv:cond-mat/0506163 · doi:10.1016/j.physb.2006.01.263

Abstract

CeNi $_{9}$ Ge $_{4}$ exhibits unusual non-Fermi liquid behavior with the largest ever recorded value of the electronic specific heat $I^ C / T ≅ 5.5$ JK $^{- 2}$ mol $^{- 1}$ without showing any evidence of magnetic order. Specific heat measurements show that the logarithmic increase of the Sommerfeld coefficient flattens off below 200 mK. In marked contrast, the local susceptibility $I^ I ¨ $ levels off well above 200 mK and already becomes constant below 1 K. Furthermore, the entropy reaches 2 $R$ ln2 below 20 K corresponding to a four level system. An analysis of $C$ and $I ¨ $ was performed in terms of an $S U (N = 4)$ single impurity Anderson model with additional crystal electric field (CEF) splitting. Numerical renormalization group calculations point to a possible consistent description of the different low temperature scales in $I^ c$ and $I^ I ¨ $ stemming from the interplay of Kondo effect and crystal field splitting.

2 pages, 2 figures

Unusual Non-Fermi Liquid Behavior of Ce1−x​Lax​Ni9​Ge4​ Analyzed in a Single Impurity Anderson Model with Crystal Field Effects

Abstract

Unusual Non-Fermi Liquid Behavior of Ce $_{1 - x}$ La $_{x}$ Ni $_{9}$ Ge $_{4}$ Analyzed in a Single Impurity Anderson Model with Crystal Field Effects