Polarized X-ray Absorption Studies in Double-Thallium-Layer Superconducting

J. M. Chen ； R. G. Liu ； R. S. Liu ； H. C. Lin ； T. M. Uen ； J. Y. Juang ； Y. S. Gou

《Chinese Journal of Physics》 36卷2S期 (1998/04) Pp. 330-335

並列摘要

Polarization-dependent 0 1s X-ray absorption spectra of highly c-axis-oriented TI2Ba2Ca2Cu3O10 (Tl-2223) and Tl2Ba2CaCu2O8 (Tl-2212) superconducting thin films have been measured by using synchrotron radaition. Near the 0 1s absorption edge, three distinct pre-edge peaks for both systems were clearly revealed. The low-energy pre-edge peak at 528.3 eV has mainly 0 2pxy symmetry, while the pre-edge peak at 529.4 eV has predominantly 0 2pz character. The spectral weight of the pre-edge peak at 528.3 eV, originating from the CuO2 planes, increase about 60% from the Tl-2212 to Tl-2223 thin films. Conversely, the high-energy pre-edge peak at 530.3 eV, originating from the TlO planes, is lower in spectral intensity by ~ 30% in Tl-2223 as compared to the Tl-2212 thin film. The experimental results clearly demonstrates the pictures of the seif doping due to the charge transfer from the CuO2 layers to the TlO layers.