Polarized X-Ray Absorption Spectroscopic Study on Mercuric Bromide Intercalated Bi2Sr2CaCu2Oy Single Crystal

Polarized X-ray absorption spectroscopic experiments have been carried out for the mercuric bromide intercalated Bi2Sr2CaCu2Oy single crystal, in order to understand the variation of anisotropic resistivities upon HgBr2 intercalation as well as to probe the electronic structure of HgBr2 intercalate. The Br K- and Bi LIII-edge spectra indicate a significant electron transfer from bismuth to bromine, implying an overlap between Bi 6s and Br 4p orbitals. From the Hg LIII- and Br K-edge data, it is also found that HgBr2 intercalation gives rise to an electron localization in the (Hg-Br) bond, which leads to poor electronic conduction along the intercalant layer. In this context, the semiconducting out-of-plane resistivity of HgBr2 intercalate can be explained by the poor conductivity of the intercalated HgBr2 layer, even though the orbital overlap between Bi and Br facilitates the electron conduction between host and guest along the c-axis