Competing ground states in heavy-fermion materials

Competing interactions in the presence of coupled spin, charge, and lattice degrees of freedom in heavy-fermion materials lead to a near degeneracy of ground states in some systems. A small perturbation in unit-cell volume or composition subsequently can produce a qualitative change in the ground st...

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Bibliographic Details
Published inJournal of alloys and compounds Vol. 303; pp. 239 - 244
Main Authors Thompson, J.D, Hegger, H, Louca, D, Kwei, G.H, Movshovich, R, Petrovic, C, Sarrao, J.L
Format Journal Article
LanguageEnglish
Published Elsevier B.V 24.05.2000
Subjects
Heavy fermions
Kondo effects
Neutron diffraction
Phase transitions
Pressure
Thermal expansion
Thermal expansion
Heavy fermions
Neutron diffraction
Pressure
Phase transitions
Kondo effects
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Summary:Competing interactions in the presence of coupled spin, charge, and lattice degrees of freedom in heavy-fermion materials lead to a near degeneracy of ground states in some systems. A small perturbation in unit-cell volume or composition subsequently can produce a qualitative change in the ground state, for example, from magnetically ordered to superconducting, with, in some instances, the appearance of a non-Fermi-liquid (NFL) state near their boundary. We have studied two heavy-fermion materials, CeCu 2Si 2 and CeRh 2Si 2, which illustrate these behaviors. Measurements of the atomic structure of CeCu 2+ x Si 2 as a function of x suggest that structural inhomogeneity may influence the preferred ground state and the existence of NFL behavior in this material. Thermal expansion measurements on CeRh 2Si 2 as a function of pressure reveal the evolution of spin-lattice coupling as the balance between RKKY and Kondo interactions is tuned by small volume changes.
ISSN:0925-8388
1873-4669
DOI:10.1016/S0925-8388(00)00666-6