Impurity bands in Kondo insulators

Journal Article · Wed Jul 01 04:00:00 EDT 1992 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.46.998· OSTI ID:5071913

Schlottmann, P ^[1]

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1. Department of Physics and Center for Materials Research and Technology, Florida State University, Tallahassee, Florida 32306 (United States)

Kondo insulators like Ce{sub 3}Bi{sub 4}Pt{sub 3} and CeNiSn are compounds with small-band-gap semiconductor properties. Nonmagnetic impurities, so-called Kondo holes, break the translational invariance and hence the coherence of the ground state. Isolated impurities give rise to a bound state in the gap, which pins the Fermi level and has magnetic properties (Curie susceptibility and Schottky anomaly in the specific heat). A finite concentration of Kondo holes gives rise to an impurity band inside the gap of the {ital f}-electron density of states, whose height and width are proportional to {radical}{ital c} for small concentrations. The specific heat is proportional to {ital T} at very low temperatures and the susceptibility is Pauli-like at low {ital T}. The correlations within the {ital f} band are introduced via a self-energy, evaluated to second-order perturbation in {ital U}. We use the (1/{ital d})-expansion method of Schweitzer and Czycholl to leading order in which the {bold k} integrations are properly carried out, but the {bold k} dependence of the self-energy is neglected. The main effect of {ital U} is to narrow the gap, as well as the impurity band.

• DOE Contract Number: FG05-91ER45443
• OSTI ID: 5071913
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 46:2; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
BISMUTH COMPOUNDS
BOUND STATE
CERIUM COMPOUNDS
ENERGY GAP
KONDO EFFECT
MAGNETIC PROPERTIES
MAGNETIC SUSCEPTIBILITY
PERTURBATION THEORY
PHYSICAL PROPERTIES
PLATINUM COMPOUNDS
RARE EARTH COMPOUNDS
SPECIFIC HEAT
TEMPERATURE EFFECTS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS