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Photoemission study of Bi/sub 2/(Sr,Ca)/sub 3/Cu/sub 2/O/sub y/

Journal Article · · Phys. Rev. B: Condens. Matter; (United States)

The electronic structure of Bi/sub 2/(Sr,Ca)/sub 3/Cu/sub 2/O/sub y/ has been studied by photoemission and electron-energy-loss spectroscopy (EELS). From analysis of the Cu 2p core-level photoemission spectra, the Cu 3d-O 2p bond in the CuO/sub 2/ layer is found to be more ionic than that in La/sub 2-//sub x/Sr/sub x/CuO/sub 4/ and YBa/sub 2/Cu/sub 3/O/sub y/, which leads to a weaker superexchange coupling between the Cu/sup 2+/ spins within the layer. Valence-band photoemission and EELS spectra suggest a significant shift of the Bi 6s contribution from the deep-lying Bi 6s-O 2p bonding states to the antibonding states in the O 2p band region as compared to the results of band-structure calculations on Bi/sub 2/Sr/sub 2/CaCu/sub 2/O/sub 8/. This is probably due to excess oxygen atoms around Bi, which may raise the Bi 6s orbital energy and provide the system with holes.

Research Organization:
Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan
OSTI ID:
6757607
Journal Information:
Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:4; ISSN PRBMD
Country of Publication:
United States
Language:
English