Superconducting energy gap and a normal-state excitation in Ba sub 0. 6 K sub 0. 4 BiO sub 3
- IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (US)
- Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439
- University of Southern California, Los Angeles, California 90089
- University of California, Santa Barbara, Santa Barbara, California 93106
We report the first measurement of the energy gap of the high-temperature bismuth oxide superconductor Ba{sub 0.6}K{sub 0.4}BiO{sub 3} ({ital T}{sub {ital c}}{approx equal}30 K). With temperature- and magnetic-field-dependent infrared reflectivity measurements, we obtain a reduced energy gap of 2{Delta}/{ital kT}{sub {ital c}}{approx equal}3.5{plus minus}0.5, consistent with a BCS-type mechanism with moderate or weak coupling. In the normal state a broad peak in the infrared conductivity is observed near 5000 cm{sup {minus}1}. This unusual infrared behavior is common to both the BaPb{sub 1{minus}{ital x}}Bi{sub {ital x}}O{sub 3} and the Ba{sub 1{minus}{ital x}}K{sub {ital x}}BiO{sub 3} systems and may provide a fundamental clue to the mechanism of superconductivity in the cubic bismuth oxides.
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 5486017
- Journal Information:
- Physical Review (Section) B: Condensed Matter; (USA), Journal Name: Physical Review (Section) B: Condensed Matter; (USA) Vol. 40:10; ISSN PRBMD; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
656100 -- Condensed Matter Physics-- Superconductivity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALKALI METAL COMPOUNDS
ALKALINE EARTH METAL COMPOUNDS
BARIUM COMPOUNDS
BARIUM OXIDES
BCS THEORY
BISMUTH COMPOUNDS
BISMUTH OXIDES
CHALCOGENIDES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ENERGY GAP
MAGNETIC FIELDS
MATHEMATICAL MODELS
NUCLEAR MODELS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POTASSIUM COMPOUNDS
POTASSIUM OXIDES
SUPERCONDUCTIVITY
TEMPERATURE DEPENDENCE
WEAK-COUPLING MODEL