ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
As-grown surfaces of c-axis-oriented laser-ablated YBa2Cu3Oy (YBCO) films have been investigated by scanning tunneling microscopy and spectroscopy (STM/STS) at 4.2 K. The square atomic arrangement with an average spacing of 0.4 nm was observed on the specimens even after exposure to ambient atmosphere, indicating that the (001) surface of the YBCO thin film was stable and free from severe contamination or chemical reaction. The STS observations revealed the semiconductive nature of the surface with a band gap of 0.1 eV. However, the tunneling spectrum varied its shape depending on the tip-to-sample distance and a clear superconducting gap structure with 2Δ∼40 meV appeared when the STM tip was closer to the surface than the usual position of the scanning mode, suggesting that the semiconductive layer is confined in the surface region of atomic size thickness.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.355720
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