Anisotropy and oxygen-stoichiometry dependence of the dielectric tensor of YBa sub 2 Cu sub 3 O sub 7 minus. delta. (0 le. delta. le 1)

Journal Article · Mon Jul 01 04:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.44.217· OSTI ID:5776319

Kircher, J; Kelly, M K; Rashkeev, S; Alouani, M; Fuchs, D; Cardona, M ^[1]

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1. Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstrasse 1, D-7000 Stuttgart 80, Federal Republic of Germany (DE)

The dielectric tensor elements of oriented YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} samples, as obtained by spectroscopic ellipsometry, are presented for several oxygen stoichiometries in the photon energy range between 1.66 and 5.5 eV. For {delta}=0 and 1, we extend this range up to 9.5 eV using a recently developed synchrotron radiation ellipsometer. We compare the experimental results with computed values for the dielectric function obtained from a linear-muffin-tin-orbitals band-structure calculation. We find good general agreement for both the orientational and compositional dependence. In particular, both experiment and theory show {ital c} polarization for a peak near 2.7 eV for {delta}{lt}0.5, while a transition in that spectral region is {ital a} polarized for YBa{sub 2}Cu{sub 3}O{sub 6}. In spite of the difficulty in predicting insulating behavior of the low-oxygen material, these results show that the local-density-approximation picture is successful in describing much of the electronic structure determining higher-energy excitations. In addition, the measured dependence of the dielectric tensor on the oxygen stoiochiometry provides a reference for optical determination of the oxygen content and orientation in applications, such as thin-film or single-crystal growth.

• OSTI ID: 5776319
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 44:1; ISSN PRBMD; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
ALKALINE EARTH METAL COMPOUNDS
AMINES
AMMONIUM COMPOUNDS
ANISOTROPY
BARIUM COMPOUNDS
BARIUM OXIDES
BIREFRINGENCE
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
DIELECTRIC TENSOR
ELEMENTS
ELLIPSOMETRY
ENERGY RANGE
EV RANGE
EV RANGE 01-10
HIGH-TC SUPERCONDUCTORS
MEASURING METHODS
NONMETALS
ORGANIC COMPOUNDS
OXIDES
OXYGEN
OXYGEN COMPOUNDS
QUATERNARY COMPOUNDS
REFRACTION
STOICHIOMETRY
SUPERCONDUCTORS
TENSORS
TRANSITION ELEMENT COMPOUNDS
YTTRIUM COMPOUNDS
YTTRIUM OXIDES