Electron tunneling spectroscopy of single-crystal Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8
- Polytechnic University, Brooklyn, New York 11201 (United States)
The {ital T}-dependent conductance {ital G}({ital V},{ital T}) of evaporated Pb junctions on cleaved {ital ab} planes of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (2:2:1:2) crystals is presented. Strong superconducting {ital G}{sub {ital s}}({ital V},{ital T}) structures imply a large gap, approximately {Delta}{sub 0}(0)=26 meV, or 2{Delta}{sub 0}(0)/{ital k}{sub {ital B}T{ital c}}=6.7. An analysis of {ital G}({ital V},{ital T}) near {ital T}{sub {ital c}}, assuming a lifetime-broadened BCS {ital N}{sub {ital s}}({ital E}), reveals a broadening {Gamma}({ital T}) such that {Delta}({ital T}{sub {ital c}}){approx}{Gamma}({ital T}{sub {ital c}}){approx}2{ital k}{sub {ital B}T{ital c}}. The fitted {Delta}({ital T}{sub {ital c}}), unlike typical BCS values, is {approx}0.8{Delta}(0). $G(V,T{gt}T sub c )--- has a minimum at {ital V}=0, suggestive of known {ital c}-direction localization in 2:2:1:2 compounds. {ital G}({ital V},{ital T}) also reveals the expected fluctuation superconductivity above {ital T}{sub {ital c}}. 4.2-K scanning-tunneling-microscope (STM) spectra are mentioned in comparison. A larger gap, about 40 meV, and dip at 80 meV, found in the STM {ital G}({ital V}) are tentatively attributed to CuO{sub 2} planes.
- DOE Contract Number:
- FG02-87ER45301
- OSTI ID:
- 7293146
- Journal Information:
- Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 45:18; ISSN 0163-1829; ISSN PRBMD
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ALKALINE EARTH METAL COMPOUNDS
BCS THEORY
BISMUTH COMPOUNDS
BISMUTH OXIDES
CALCIUM COMPOUNDS
CALCIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
ENERGY GAP
HIGH-TC SUPERCONDUCTORS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TEMPERATURE EFFECTS
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION TEMPERATURE