X-ray absorption study of oxygen in the high-Tc superconductor Bi2Sr2CaCu2O8 near the interfaces to Cu, Ag and Au

• The influence on O 2p holes in single crystalline Bi2Sr2CaCu2O8 upon the interface formation to Cu, Ag and Au has been studied by O K edge X-ray absorption measurements. It was found that Cu reduces the amount of doping induced O 2p holes significantly in the vicinity of the interface, whereas Ag and Au gave a much smaller reduction of these states. Photoemission spectra confirmed previous findings that Cu causes a strong chemical reaction at the Bi-O surface of Bi2Sr2CaCu2O8, in contrast to Ag and Au which induced only a minimal reaction. The results support the opinion that the Bi-O layers are essential for the doping of the Cu-O2 layers in Bi2Sr2CaCu2O8.

Nyckelord

Cu-O planes

Hole concentration

Metal overlayer

Normal state properties

XAFS

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