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TT: Tiefe Temperaturen

TT 13: HTSL: Ramanstreuung, elektronische Struktur

TT 13.9: Vortrag

Mittwoch, 19. März 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)