The electronic structure of Bi2.0Sr1.8La0.3Ca0.8Cu2.1O8+δ superconductors studied using ultraviolet and X-ray photoelectron spectroscopy

Photoemission measurements on single crystals of La-doped 2212 (Bi2.0Sr1.8La0.3Ca0.8Cu2.1O8+δ) superconductors were carried out utilizing both synchrotron and Al Kα (1486.6 eV) radiation. A quantitative analysis of the photoemission data in comparison with similar data for the undoped 2212 material indicates that the La atoms preferentially occupy the Sr sites in the SrO layer next to the BiO plane. Evidence of alternation of the electronic environment of the Bi atoms is found in the Bi 5d core level spectra which show a shoulder at ≈ 1.2 eV higher binding energy, presumably due to the partial substitution of trivalent La ions (La³⁺) for divalent Sr ions (Sr²⁺). As for the undoped 2212 material, the photoemission spectra reveal a clear Fermi level cut-off at room temperature, single component O ls core level emission, and a Cu 2p satellite to main line intensity ratio of 0.4. © 1989.

Duke Scholars

Author David Mitzi Thomas Lord Department of Mechanical Engineering and Materia ...