Browsing by Author "Park, M"

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Hole states of X-Bi2Sr2CaCu2O8 [X=I, HgI2, and (Py-CH3)(2)HgI4] probed by OK-edge X-ray absorption spectroscopy
(2006-01-01)
Chen, JM
;
Chang, SC
;
Liu, RS
;
Lee, JM
;
Park, M
Hole states of X-Bi2Sr2CaCU2O8[X-Bi2212, X=I, HgI2, and (Py-CH3)(2)-HgI4, Py = pyridinel have been probed by O K-edge X-ray absorption near-edge structure (XANES) spectra. In the O 1s absorption edge of X-Bi2212, the pre-edge peak at similar to 528.3 eV is attributed to transitions into the 0 2p hole states located in the CuO2 planes. The hole concentration in the CuO2 planes of X-Bi2212 increases for X =I and HgI2, but decreases for X= (Py-CH3)(2)HgI4 as coMPared to pristine Bi2212. The variation of CuO2-plane hole concentration of Bi2212 is primarily responsible for the T-c variation upon intercalation. (c) 2005 Elsevier Ltd. All rights reserved.
Soft-x-ray absorption spectroscopy of heterostructured high-T-c superconducting nanohybrids: X-Bi2Sr2CaCu2O8 [X=I, HgI2, and (Py-CH3)(2)HgI4]
(2005-03-01)
Chen, JM
;
Chang, SC
;
Liu, RS
;
Lee, JM
;
Park, M
Unoccupied electronic states of X-Bi2Sr2CaCu2O8 [X-Bi2212, X=1, HgI2, and '(Py-CH3)(2)-HgI4, Py =pyridine] have been probed by O K-edge and Cu L-edge x-ray absorption near-edge structure (XANES) spectra using a bulk-sensitive x-ray-fluorescence-yield technique. In the 0 Is absorption edge of X-Bi2212, the pre-edge feature at similar to 528.3 eV is attributed to transitions into O 2p hole states located in the CuO2 planes. As deduced from 0 K-edge and Cu L-edge x-ray absorption spectra, the hole concentration in the CuO2 planes of X-Bi2212 increases for X=I and HgI2, but decreases for X= (Py-CH3)(2)HgI4, relative to pristine Bi2212. The present XANES results clearly demonstrate that the hole density within the CuO2 planes of intercalated Bi2Sr2CaCu2O8 can be not only decreased but also increased, depending on the chemical character of the intercalants.