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Quadruple perovskites {ital L}{sup {prime}}{ital L}{sup {double_prime}}Ba{sub 2}Cu{sub 2}Ti{sub 2}O{sub 11} as good candidates for high-temperature superconductors: Role of oxygen defects

Journal Article · · Physical Review, B: Condensed Matter
;  [1];  [2]
  1. Science and Technology Center for Superconductivity, Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208-3112 (United States)
  2. Science and Technology Center for Superconductivity, Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3112 (United States)
The electronic structure and properties of LaYBa{sub 2}Cu{sub 2}Ti{sub 2}O{sub 11}, as a typical member of the {ital L}{sup {prime}}{ital L}{sup {double_prime}}Ba{sub 2}Cu{sub 2}Ti{sub 2}O{sub 11} family, were determined by means of the full-potential linear muffin-tin method. From the results obtained it appears that {ital L}{sup {prime}}{ital L}{sup {double_prime}}Ba{sub 2}Cu{sub 2}Ti{sub 2}O{sub 11} may be a good candidate for high-{ital T}{sub {ital c}} superconductivity since its band structure at the Fermi energy is dominated by a quasi-two-dimensional Cu-O {ital dp}{sigma} band with a prominent van Hove singularity. We suggest that hole doping of about 0.6 holes per unit cell (or 0.3 holes per Cu-O layer) through mono- and/or divalent metal substitution for lanthanides may lead to an optimum {ital T}{sub {ital c}} in these materials. The role of different structural imperfections on the {ital T}{sub {ital c}} that apparently could be created in the process of chemical doping {emdash} oxygen impurities between the Cu-O layers and oxygen vacancies in the Ti-O plane {emdash} was also determined. We found that these likely structural imperfections are unfavorable for the creation of the superconducting state in these materials. {copyright} {ital 1996 The American Physical Society.}
OSTI ID:
280206
Journal Information:
Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 14 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
Country of Publication:
United States
Language:
English