Intracrystalline structure of molecular mercury halide intercalated in high-T{sub c} superconducting lattice of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y}
- Seoul National Univ. (Korea, Republic of)
X-ray absorption spectroscopic studies have been systematically carried out for the new high-T{sub c} superconducting intercalation compounds, (HgX{sub 2}){sub 0.5}Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} (X = Br and I), with a hybridized crystal lattice consisting of superconducting layer and insulating one. From the Hg Lm-edge EXAFS analysis, it is found for the first time that the intercalated mercuric halide is stabilized as a linear molecule with the bond distance (Hg-X) of 2.46 A for the HgBr{sub 2} intercalate and 2.65 A for the HgI{sub 2} one, respectively. These are cross-confirmed not only by micro-Raman studies but also by one-dimensional electron density mapping based on (001) X-ray reflections, which is well consistent with the EXAFS fitting results. The present I L{sub I}- and Br K-edge XANES results indicate a partial electron transfer from the host lattice of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub y} to the intercalant HgX{sub 2} layer with the partial oxidations of Bi{sub 2}O{sub 2} and CuO{sub 2} layers. And the latter was also observed clearly form the Bi L{sub III}-edge XANES and Cu K-edge EXAFS analyses, which are in good agreement with the I L{sub I}- and Br K-edge XANES results. It is, therefore, concluded that the charge transfer between host and guest is mainly responsible for the T{sub c} evolution upon intercalation, and the T{sub c} of this compound is surely related to the variation of hole concentration rather than electronic coupling along the c-axis. 73 refs., 12 figs., 5 tabs.
- OSTI ID:
- 466310
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 7 Vol. 119; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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