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Author Schlottmann, P.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS ♦ KONDO EFFECT ♦ IMPURITIES ♦ SEMICONDUCTOR MATERIALS ♦ CERIUM COMPOUNDS ♦ YTTERBIUM COMPOUNDS ♦ URANIUM COMPOUNDS ♦ ELECTRONIC STRUCTURE ♦ THERMODYNAMIC PROPERTIES ♦ MAGNETIC PROPERTIES ♦ PHASE TRANSFORMATIONS ♦ EXCHANGE INTERACTIONS
Abstract Kondo insulators like Ce{sub 3}Bi{sub 4}Pt{sub 3} and CeNiSn are compounds with small-gap semiconductor properties. The Kondo insulator is described by the nondegenerate symmetric Anderson lattice with, on average, two electrons per site within Kotliar and Ruckenstein{close_quote}s mean-field approximation in terms of four slave bosons per site. A Kondo hole is the charge neutral substitution of a rare earth or actinide atom by a nonmagnetic analog. An isolated Kondo hole gives rise to a bound state in the gap, which pins the Fermi level and has magnetic properties. A finite concentration of Kondo holes generates an impurity band in the gap of the semiconductor. The low-temperature thermodynamic and transport properties are determined by the impurity band. The interplay of the {ital f}-electron correlations with the impurity band is studied in the paramagnetic phase. On a bipartite lattice the pure Kondo insulator is unstable to long-range antiferromagnetism for {ital U}{approx_gt}{ital U}{sub {ital c}} and to ferromagnetism in sufficiently large magnetic fields. A small concentration of Kondo holes reduces the threshold for the antiferromagnetic transition, giving rise to reentrance, but does not substantially affect ferromagnetism. {copyright} {ital 1996 The American Physical Society.}
ISSN 01631829
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-11-01
Publisher Place United States
Journal Physical Review, B: Condensed Matter
Volume Number 54
Issue Number 17


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