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TT: Tiefe Temperaturen
TT 13: HTSL: Ramanstreuung, elektronische Struktur
TT 13.9: Talk
Wednesday, March 19, 1997, 17:00–17:15, F2
High energy spectroscopic studies of single crystalline Sr2CuO2Cl2 — •T. Böske, O. Knauff, R. Neudert, M. Knupfer, M. S. Golden, G. Krabbes, and J. Fink — Institut für Festkörper- und Werkstofforschung Dresden, Postfach 270016, D-01171 Dresden
X-ray photoemission spectroscopy (XPS) and electron energy-loss spectroscopy (EELS) in transmission is applied to study the electronic structure of the insulating layered cuprate compound Sr2CuO2Cl2. This oxyhalide contains CuO2 planes, separated by ionic SrCl double block layers and can be regarded as a model substance within the cuprates for the dynamics of valence band holes in two dimensions. We present and discuss XPS core level, valence band and Auger spectra. From the EELS data, the dielectric function and the electron-hole pair excitations along the high symmetry directions of the CuO2 plane have been obtained.
The Cu 2p XPS differs from the spectra of other cuprate compounds, as it is comprised of more than two peaks and the satellite emission is found to be intense with a distinct angular dependent fine structure. We compare our results to calculations of a Cu5O16 cluster in the d–p model[1] in order to obtain an understanding of these features and discuss the Cu 2p spectrum in terms of the different screening mechanisms available in CuO2 planes.
[1] K. Okada and A. Kotani, Phys. Rev. B 52, 4794 (1995)