Temperature-dependent tunneling spectra of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals with well-defined Bi{sub 2}Sr{sub 2}CuO{sub 6} epitaxial layers
- Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki, Osaka 567 (Japan)
The temperature dependence of the tunneling conductance {ital G}({ital V},{ital T}) along the {ital c} axis of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystals has been investigated using epitaxial junctions of the type Au/Bi{sub 2}Sr{sub 2}CuO{sub 6} thin-film layer/Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} single crystal. A linear background conductance is observed, which appears to originate from a normal density-of-states effect. The background can be adequately described by a simple first-order relation using only one fitting parameter. The shape of the superconducting gap agrees well with a convolution of this linear background and a BCS-like density of states that includes Andreev reflection. The fits yield values for the ratio 2{Delta} ({ital T}=11 K)/{ital k}{sub {ital B}}{ital T}{sub {ital c}} (84 K)=5.4--6.0 and a very small lifetime width {Gamma} ({ital T}=11 K){lt}0.1 meV. The data suggest that the zero-bias conductance is intrinsically low or zero, suggesting an {ital s}-like character for the superconducting pairing function along the {ital c} axis in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8}.
- OSTI ID:
- 76432
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 1 Vol. 52; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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