Increased density of the in-plane and out-of-plane doping holes in the superconducting state of HgBa2Ca2Cu3Oy

Abstract

We have studied the electronic structure near the Cu-O planes in the normal and superconducting states in a high-quality HgBa2Ca2Cu3Oy thick film using polarized x-ray absorption in order to get quantitative information on the changes in density and symmetry of the itinerant holes. We have observed, in our analysis of the Cu L3-edge absorption spectra, an increase in the density of doping holes along the planes parallel and perperdicular to the Cu-O sheets while going from the normal to the superconducting state. Our results show that some of the holes have 3dz2 symmetry and moreover their density also increases as the system goes to the superconducting state. The results have been discussed in light of the earlier published results on other cuprate superconducting systems and a probable local and short-range structural change in the CuO5 pyramid which may be associated with the superconducting transition.

Source-reported materials — not catalogue approval

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