Anisotropic dielectric function and electronic structure of the infinite-layer compound (Sr1-xCax)yCuO2

Y. Y. Wang*, H. Zhang, Vinayak P Dravid, P. D. Han, D. A. Payne

*Corresponding author for this work

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The electronic structure and dielectric functions of single crystallites of the infinite-layer compound (Sr1-xCax)yCuO2 (y=0.90, x=0.3) are investigated by transmission-electron-energy-loss spectroscopy with a cold-field emission-gun TEM. The band gap along the c axis is estimated to be significantly greater than in the aa plane, which suggests anisotropic electronic properties. Unlike other cuprates, oxygen core-loss spectra of this compound display two distinct preedge peaks. A close correlation was observed between the valence-band excitations below 10 eV in the aa plane and the oxygen K core-loss fine structure. The ∼2 eV excitation in the valence-band spectrum is associated with a transition from the lower Hubbard band to the upper Hubbard band and is detected only in the aa plane. This excitation coincides with the first preedge peak in O K core-loss spectra, which is assigned to a transition from the O 1s state to the upper Hubbard band. The results are consistent with the band-structure calculations, for the infinite-layer compound, which indicate strong Cu 3d-O 2p hybridization within the aa plane, but little overlap of the wave function along the c axis.

Original languageEnglish (US)
Pages (from-to)9810-9814
Number of pages5
JournalPhysical Review B
Volume48
Issue number13
DOIs
StatePublished - Jan 1 1993

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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