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TT: Tiefe Temperaturen
TT 21: Metall Isolatorüberg
änge
TT 21.6: Vortrag
Donnerstag, 29. März 2001, 10:45–11:00, J
Visible and Near Infrared Ellipsometric Investigation of the Temperature Dependent Optical Properties of La2−xSrxCuO4 — •Todd Holden1, C Bernhard1, B Keimer1, M Cardona1, A Wittlin2, and S Uchida3 — 1Max Planck Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany — 2Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32, Warszawa, Poland — 3Department of Superconductivity, University of Tokyo, Yagoi 2-11-16, Bunkyo-Ku, Tokyo 113, Japan
Using spectral ellipsometry, we have determined the in-plane and c-axis optical constants of La2−xSrxCuO4 (x=0.1- 0.2) in the spectral range 0.5-5.5 eV for temperatures ranging from 20K to 330K. The c-axis spectra show a temperature dependent feature centered near 1 eV. A considerable spectral weight gain is observed for incresing temperatures. This gain is most pronounced at temperatures much higher than Tc and thus is more likely related to the pseudo-gap effect rather than superconductivity. The a-axis spectra show a clear plasma-edge as well as some weak features between 1 and 3 eV probably related to charge transfer excitations.