c -axis oxygen in copper oxide superconductors

Journal Article · Sat Jun 30 20:00:00 EDT 1990 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.42.138· OSTI ID:6766832

Manthiram, A; Tang, X X; Goodenough, J B ^[1]

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1. Center for Materials Science and Engineering, The University of Texas at Austin, Austin, Texas 78712 (USA)

Exploration of the roles of {ital c}-axis oxygen in the copper-oxide superconductors has revealed a new type of tetragonal-orthorhombic transition in the system {ital R}{sub 2{minus}{ital z}}Ce{sub {ital z}}Ba{sub 2{minus}{ital y}L{ital y}}Cu{sub 3}O{sub 8+{ital x}}({ital R}=Nd or Gd, {ital L}=La or Nd) and one probably due to cluster rotation in fluorinated La{sub 2{minus}{ital y}}Dy{sub {ital y}}CuO{sub 4{minus}{ital x}}F{sub 2{ital x}} having the {ital T}{sup *} structure with interstitial F ordered in the rocksalt layer. The former is due to {ital c}-axis ionic displacements that relieve a compressive stress on the (Ba,{ital L})O rocksalt sheets, the latter a tensile stress on the LaO rocksalt sheets. In the YBa{sub 2}Cu{sub 3}O{sub 6+{ital x}} structure, the {ital c}-axis oxygen participates in oxygen diffusion in the superconductively inactive layers, they act as gates for stabilizing holes in Cu(1)O{sub {ital x}} planes versus CuO{sub 2} sheets, and they modulate the width {ital W} of the {sigma}{sub {ital x}}{sup 2}{minus}{ital y}{sup 2*} conduction band. These modulations are shown to be capable of changing the bandwidth from {ital W}{lt}{ital U} to {ital W}{gt}{ital U} and hence to provide a rationalization for the nonsuperconducting metallic copper oxides containing copper in a formal valence state greater than 2+. As modulators of bandwidth, their displacements offer electron-lattice interactions for pairing superconductive holes. In the {ital n}-type superconductors, interstitial {ital c}-axis oxygen perturbs the {sigma}{sub {ital x}}{sup 2}{minus}{ital y}{sup 2*} band so as to introduce localized states at the band edges that suppress superconductivity.

• OSTI ID: 6766832
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 42:1; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360202* -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BOND LENGTHS
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
CRYSTAL-PHASE TRANSFORMATIONS
DIMENSIONS
GADOLINIUM COMPOUNDS
GADOLINIUM OXIDES
HIGH-TC SUPERCONDUCTORS
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
LENGTH
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
RARE EARTH COMPOUNDS
SUPERCONDUCTORS
TETRAGONAL LATTICES
TRANSITION ELEMENT COMPOUNDS