X-ray-absorption study of charge-density ordering in (Ba sub 1 minus x K sub x )BiO sub 3

Journal Article · Wed Nov 01 04:00:00 EST 1989 · Physical Review (Section) B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.40.8828· OSTI ID:5210728

Heald, S M; DiMarzio, D ^[1]; Croft, M; Hegde, M S ^[2]; Li, S; Greenblatt, M ^[3]

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1. Materials Science Division, Brookhaven National Laboratory, Upton, New York 11973 (USA)
2. Physics Department, Rutgers University, Piscataway, New Jersey 08855 (USA)
3. Department of Chemistry, Rutgers University, Piscataway, New Jersey 08855 (USA)

Temperature-dependent x-ray-absorption measurements have been made on the Bi {ital L}{sub 3} edge in (Ba{sub 1{minus}{ital x}}K{sub {ital x}})BiO{sub 3} with {ital x}=0 and 0.4. In the near-edge spectra there is clear evidence for Bi(6{ital s}) holes that depend on doping, but there does not seem to be a significant amount of Bi disproportionation into the 5+ and 3+ valencies in the undoped material. The extended x-ray-absorption fine-structure (EXAFS) measurements confirm previous diffraction studies of the structure and were also used to determine the EXAFS Debye-Waller factor for a number of Bi bonds. For {ital x}=0 the Debye-Waller factor differs strongly for the two types of Bi-O bonds, while for {ital x}=0.4 there is significant increase in the temperature-independent contribution. All of the temperature data could be fit well with an Einstein model, except for the Bi-O bond in a superconducting sample that showed a significant deviation from the expected behavior. These results, along with other considerations, are best explained by associating the charge-density ordering in the undoped material with holes on the O lattice and a tendency in the cubic superconducting sample towards the same type of charge-density-driven distortions.

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5210728
• Journal Information: Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:13; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION SPECTRA
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
BARIUM COMPOUNDS
BISMUTH COMPOUNDS
CHEMICAL BONDS
DEBYE-WALLER FACTOR
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FINE STRUCTURE
HOLES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
QUATERNARY COMPOUNDS
SPECTRA
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
X-RAY SPECTRA