Positron trapping at defects in copper oxide superconductors

Journal Article · Wed May 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.10422· OSTI ID:5622608

McMullen, T; Jena, P; Khanna, S N; Li, Y ^[1]; Jensen, K O ^[2]

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1. Physics Department, Virignia Commonwealth University, Richmond, Virginia 23284-2000 (USA)
2. School of Physics, University of East Anglia, Norwich NR47TJ, United Kingdom (GB)

Positron states and lifetimes at defects in the copper oxide superconductors La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4}, YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}}, and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{ital x}} are calculated with use of the superposed-atom model. In the Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{ital x}} compound, we find that the smaller metal-ion vacancies appear to only bind positrons weakly, while missing oxygens do not trap positrons. In contrast, metal-ion vacancies in La{sub 2{minus}{ital x}}Sr{sub {ital x}}CuO{sub 4} and YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} bind positrons by {similar to}1 eV, and oxygen-related defects appear to be the weak-binding sites in these materials. The sites that bind positrons only weakly, by energies {similar to}{ital k}{sub {ital B}T}, are of particular interest in view of the complex temperature dependences of the annihilation characteristics that are observed in these materials.

• OSTI ID: 5622608
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:13; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
ANTILEPTONS
ANTIMATTER
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BARIUM COMPOUNDS
BARIUM OXIDES
BINDING ENERGY
BISMUTH COMPOUNDS
BISMUTH OXIDES
BLOCH THEORY
CALCIUM COMPOUNDS
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CHALCOGENIDES
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CRYSTAL DEFECTS
CRYSTAL STRUCTURE
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ENERGY
ENERGY LEVELS
FERMI LEVEL
FERMIONS
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LEPTONS
LIFETIME
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OXYGEN COMPOUNDS
POINT DEFECTS
POSITRONS
RARE EARTH COMPOUNDS
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
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TRANSITION ELEMENT COMPOUNDS
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