Abstract
In this paper, we briefly review some recent de Haas–van Alphen experiments on two contrasting types of heavy fermion/Kondo systems for varying concentrations x of the impurity ion, Ce or U. In both systems the Fermi surface is observed to vary continuously with x: in Ce x La 1− x B 6, the Ce ions behave as Kondo impurities while in U x Th 1− x Be 13 they do not. In both systems, the f electrons are also found to contribute only partially to the Fermi surface volume, therefore raising questions concerning the applicability of Fermi liquid theory.
Highlights
The de Haas}van Alphen e!ect can provide essential information on the electronic structure of heavy fermion systems. It tells us when a material appears to behave like a Fermi liquid in the presence of a magnetic "eld, and can potentially yield important Fermi liquid parameters, such as the electron g-factor or the quasiparticle e!ective mass enhancement
One of the more common assumptions made, is that the e!ective mass measured by means of de Haas}van Alphen (dHvA) experiments is directly proportional the density of states obtained from speci"c heat measurements [1,2]
Harrison et al / Physica B 294}295 (2001) 234}239 obtained. Another matter that has been largely ignored, beyond the scope of dHvA measurements on pure heavy fermion systems is the question concerning the applicability of Luttinger's theorem and the extent to which the f electrons contribute to the Fermi surface volume [1,2]
Summary
The de Haas}van Alphen (dHvA) e!ect can provide essential information on the electronic structure of heavy fermion systems To begin with, it tells us when a material appears to behave like a Fermi liquid in the presence of a magnetic "eld, and can potentially yield important Fermi liquid parameters, such as the electron g-factor or the quasiparticle e!ective mass enhancement Harrison et al / Physica B 294}295 (2001) 234}239 obtained Another matter that has been largely ignored, beyond the scope of dHvA measurements on pure heavy fermion systems is the question concerning the applicability of Luttinger's theorem and the extent to which the f electrons contribute to the Fermi surface volume [1,2]. Tnoht\toV Bageree, the cyclotron efwith speci"c heat measurements, and in both systems, the f electrons appear to contribute to the Fermi surface volume in a non-integral manner
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