O K and Cu L-III edge study of itinerant holes in I-2-, HgI2- and HgBr2-intercalated BSCCO(2212) single crystals

Intercalation effect on BSCCO (2212) system, although it increases the inte rlayer distance and the c-axis remarkably, produces only a small change in the transition temperature. Thus, amongst other things, intercalation provi des an effective method to investigate the influence of the interblock coup ling. Electrons are transferred from the host Cu-O-2 layers to the guest lm olecules I-2, HgBr2, HgI2 leading to evolution of the Tc. For this we have made high resolution XANES study on the O K and Cu L3 edges to estimate the density of the doping holes. We attempt on basis of our and earlier result s the evolution of Tc in these as also the much larger decrease produced in Tc for I-2-intercalation for which the increase in basal spacing is the sm allest of the three halides.