Optical studies of single-crystal Nd sub 2 minus x Ce sub x CuO sub 4 minus. delta

Journal Article · Fri Mar 01 04:00:00 EST 1991 · Physical Review, B: Condensed Matter; (USA)

DOI:https://doi.org/10.1103/PhysRevB.43.5389· OSTI ID:5690599

Zhang, J; Bi, X; McRae, E; Eklund, P C ^[1]; Sales, B C; Mostoller, M ^[2]

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1. Department of Physics, University of Kentucky, Lexington, Kentucky 40506 (USA) Department of Astronomy, University of Kentucky, Lexington, Kentucky 40506 (USA)
2. Solid State Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6033 (USA)

Optical reflectivity spectra of Nd{sub 2}CuO{sub 4{minus}{delta}} and Nd{sub 1.8}Ce{sub 0.2}CuO{sub 4{minus}{delta}} single crystals for the polarization {bold E}{perpendicular}{bold c} have been investigated over an energy range from 0.005 to 6 eV. Four {ital E}{sub {ital u}} intralayer phonons are observed for Nd{sub 2}CuO{sub 4{minus}{delta}} at 121, 301, 347, and 507 cm{sup {minus}1}, in good agreement with preliminary shell-model-calculation results. The oscillator strength of a broad mid-ir band is found to depend on both oxygen deficiency and cerium doping. The far-ir optical conductivity is fit to both the recently proposed marginal-Fermi-liquid model (MFL) and the modified Drude-Lorentz model (MDL). A notch in the far-ir conductivity is observed at 24 meV, in good agreement with the MFL model. Values for the plasma frequency obtained are quite low and suggest that very large mass enhancement exists for the free carriers in these materials. A clear downshift of oscillator strength from (1--2.3)-eV charge-transfer excitation to the mid-ir band is also observed.

• OSTI ID: 5690599
• Journal Information: Physical Review, B: Condensed Matter; (USA), Journal Name: Physical Review, B: Condensed Matter; (USA) Vol. 43:7; ISSN 0163-1829; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
CERIUM COMPOUNDS
CERIUM OXIDES
CHALCOGENIDES
COPPER COMPOUNDS
COPPER OXIDES
CRYSTALS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
MEDIUM TEMPERATURE
MONOCRYSTALS
NEODYMIUM COMPOUNDS
NEODYMIUM OXIDES
OPTICAL PROPERTIES
OSCILLATOR STRENGTHS
OXIDES
OXYGEN COMPOUNDS
PHOTOCONDUCTIVITY
PHYSICAL PROPERTIES
RARE EARTH COMPOUNDS
REFLECTIVITY
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS