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TT: Fachverband Tiefe Temperaturen
TT 10: Poster Session: Superconductivity
TT 10.35: Poster
Monday, March 14, 2011, 14:00–18:00, P4
Fluctuation of the hole density of a slightly under-doped (Bi,Pb)2 Sr2CaCu2O8+δ single crystal studied by X-ray absorption spectroscopy — •Ailakbar Ghafari, Ahmad Kamal Ariffin, Robin Weyrich, Christoph Janowitz, Helmut Dwelk, Rüdiger Mitdank, Alica Krapf, and Recardo Manzke — Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, D-12489 Berlin, Germany
The effects of in-plane polarization change and temperature variation on the determination of the hole density for under-doped (Bi,Pb)-2212 single crystals by XAS have been studied. The XAS signal at the CuL3 edge (925 eV-940 eV) and O-K edge (525 eV-539 eV) was recorded under continuous rotation of the CuO2 plane by 180 degree with a minimum increment of 1.8 degree yielding experimentally an in-plane polarization dependence for the absorption signals at the respective thresholds and from that the in-plane angular dependence of the hole density (nH(φ )). Fermi’s golden rule was then used for the evaluation of the in-plane polarization dependence showing unexpected polarization independence. Second, the polarisation geometry was kept fixed and spectra were taken from room temperature to 10 K with a decrement about 10 K. While the polarization dependence nH(φ ) differed for the respective thresholds the temperature dependence showed less variation. Our results point out to the role of out of plane orbitals which is supported by Anderson and Weber [1, 2].
P. W. Anderson, Science, 235, 1196 (1987)
C. Weber, et al. Phys. Rev. B 82, 125107 (2010)