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TT: Tiefe Temperaturen
TT 15: Superconductivity - Properties, Electronic Structure, Order Parameter I
TT 15.6: Talk
Saturday, March 5, 2005, 15:30–15:45, TU H2053
STM structure analysis of Pb-doped Bi-2212 depending on the Pb-content — •Hendrik Glowatzki, Alica Krapf, Christoph Janowitz, and Recardo Manzke — Institut f. Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin
Scanning Tunneling Microscopy (STM) was used to analyse the surface modification of double layered bismuth single crystals (BSCCO) due to partial substitution of Bi by Pb resulting in Bi2−xPbxSr2CaCu2O8+δ. A typical structure found on Pb-free BSCCO is the well known (4.7x1) superstructure modulation, which can be clearly seen along the ab-(001) plane. The increasing substitution of Bi by Pb was reported to lead to a weakening of the modulation structure, thus increasing the modulated wavelength and finally disappearing at x=0,5 [1]. Depending on the Pb-content x we were able to verify the increasing wavelength, but not a complete disappearance of the modulation. We found the modulation structure not covering the whole surface but building an arrangement of domains at x≥ 0.3. Our observations show an alternation of domains, parts of which seem to be flat while others reveal the modulated structure. The structural features will be discussed in terms of the crystal composition.
[1] Lei Shi et al., J. Phys.: Condens. Matter 13, 5195 (2001)