STM images of a superconducting Cu-O plane and the corresponding tunneling spectrum in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}}
- Department of Physics, Faculty of Science, Hokkaido University, Sapporo 060 (Japan)
Clear atomic images of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} cleaved surfaces have been observed at {ital T}=6 and 300 K by scanning tunneling microscopy (STM). The atomic images taken for bias voltages much lower than the Bi-O plane semiconducting gap {ital E}{sub g}{approximately}100 meV, corresponding to the Cu-O plane, indicate that the conduction electrons exist mainly in the Cu 3{ital d}{sub {ital x}{sup 2}{minus}{ital y}{sup 2}} and O 2{ital p}{sub {sigma}} orbitals. Tunneling spectra have been also measured in the same processes as in the Cu-O plane STM image observations at {ital T}=6 K. The low-temperature spectra are in good agreement with that in a {ital d}-wave superconductor with an anisotropic Fermi surface on which the normal density of states {ital N}({bold k}{sub {ital F}}) is largest ({ital N}{sub max}) for the maximum gap directions and decreases to {approximately}{ital N}{sub max}/2 for the node directions. This, combined with the result on the {ital N}({bold k}{sub {ital F}}) anisotropy in photoemission experiments, is consistent with a {ital d}{sub {ital x}{sup 2}{minus}{ital y}{sup 2}} superconducting gap. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 278692
- Journal Information:
- Physical Review, B: Condensed Matter, Journal Name: Physical Review, B: Condensed Matter Journal Issue: 5 Vol. 53; ISSN PRBMDO; ISSN 0163-1829
- Country of Publication:
- United States
- Language:
- English
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