Electronic structure of (Tl0.5Pb0.5)Sr-2(Ca1-xYx)Cu2O7 (x=0-0.9) at 50 K probed by X-ray absorption spectroscopy
Journal
Journal De Physique Iv
Journal Volume
7
Journal Issue
C2
Pages
523-524
Date Issued
1997
Author(s)
Abstract
High-resolution O K-edge X-ray-absorption near-edge-structure (XANES) spectra for the series of (Tl0.5Pb0.5)Sr2(Ca1-xY x)Cu2O7 compounds (x = 0 - 0.9) at 50 K were measured using a bulk-sensitive X-ray-fluorescence-yield technique. A well-pronounced pre-edge peak at ∼ 528.3 eV is ascribed to the excitations of O Is electrons to O 2p holes located in the CuO2 planes. The intensity of this pre-edge peak increases with the Ca doping for 0 ≤ x ≤ 0.5. This indicates that the effect of chemical substitution of Ca2+ for Y3+ is to induce hole states in the CuO planes near the Fermi level. The generation of O 2p holes in the CuO planes is probably responsible for inducing a transition from a semiconductor to a superconductor.
Type
journal article