Soft-x-ray absorption spectroscopy of heterostructured high-T-c superconducting nanohybrids: X-Bi2Sr2CaCu2O8 X=I, HgI2, and (Py-CH3)(2)HgI4
Journal
Physical Review B
Journal Volume
71
Journal Issue
9
Date Issued
2005
Author(s)
Abstract
Unoccupied electronic states of X-Bi 2Sr 2CaCu 2O 8 [X-Bi2212, X=I, HgI 2, and (Py-CH 3) 2-HgI 4, 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 O 1s absorption edge of X-Bi2212, the pre-edge feature at ∼528.3 eV is attributed to transitions into O 2p hole states located in the CuO 2 planes. As deduced from O K-edge and Cu L-edge x-ray absorption spectra, the hole concentration in the CuO 2 planes of X-Bi2212 increases for X=I and HgI 2, but decreases for X=(Py-CH 3) 2HgI 4, relative to pristine Bi2212. The present XANES results clearly demonstrate that the hole density within the CuO 2 planes of intercalated Bi 2Sr 2CaCu 2O 8 can be not only decreased but also increased, depending on the chemical character of the intercalants. ©2005 The American Physical Society.
Type
journal article