Classification of strongly correlated f-electron systems

Journal Article · Mon May 01 04:00:00 EDT 1995 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/BF00752293· OSTI ID:107578

Steglich, F; Geibel, C; Modler, R ^[1]

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1. Institut fuer Festkoerperphysik, Darmstadt (Germany); and others

Ce-based heavy-fermion (HF) metals behave as Kondo-lattice systems and can be classified with the aid of a single coupling parameter, {vert_bar}J{vert_bar}/W, where J < 0 is the local exchange integral and W the conduction-band width. Depending on its actual composition, the exemplary material CeCu{sub 2}Si{sub 2} chooses one out of two ground states: HF superconductivity and a new magnetic HF phase {open_quotes}A{close_quotes}. In a narrow composition range, these two phases are nearly degenerate and expell each other upon varying either the temperature or the external magnetic field. The one-parameter-scaling approach appears inapplicable to the U-based HF metals. For the exemplary material UPd{sub 2}Al{sub 3}, antiferromagnetic ordering between seemingly local 5f moments coexists, on a microscopic scale, with HF superconductivity. Whether this coexistence can be explained by assuming 5f states localized on a tetravalent U-ion with non-magnetic crystal-field ground state remains to be shown. We discuss arguments which invoke itinerant 5f states in the U-based HF metals to be distinguished from the localized 4f states in the Ce-based counterparts.

• Sponsoring Organization: USDOE
• OSTI ID: 107578
• Report Number(s): CONF-9409365--
• Journal Information: Journal of Low Temperature Physics, Journal Name: Journal of Low Temperature Physics Journal Issue: 3-4 Vol. 99; ISSN JLTPAC; ISSN 0022-2291
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
66 PHYSICS
ANTIFERROMAGNETISM
CERIUM COMPOUNDS
ELECTRON CORRELATION
F STATES
FERMIONS
KONDO EFFECT
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TRANSITION TEMPERATURE
URANIUM COMPOUNDS