Doping dependence of the [ital a]-[ital b]-plane optical conductivity of single-crystal La[sub 2[minus][ital x]]Sr[sub [ital x]]NiO[sub 4+[delta]]

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.48.3470· OSTI ID:6351224

Bi, X; Eklund, P C ^[1]; Honig, J M ^[2]

---

1. Department of Physics and Astronomy and Center for Applied Energy Research, University of Kentucky, Lexington, Kentucky 40506 (United States)
2. Department of Chemistry, Purdue University, West Lafayette, Indiana 47907 (United States)

Results of room-temperature [ital a]-[ital b]-plane optical-reflection studies of La[sub 2[minus][ital x]]Sr[sub [ital x]]NiO[sub 4+[delta]] ([delta]=0.0; [ital x]=0, 0.05, 0.10, 0.20, 0.21, and [delta]=0.085; [ital x]=0) are presented and cover the photon energy range 0.005[lt][omega][lt]6 eV. A Kramers-Kronig analysis is used to compute the optical conductivity [sigma]([omega]) and energy-loss function Im([minus]1/[var epsilon]([omega])). The doping dependence of the TO and LO [ital a]-[ital b]-plane phonon modes, anomalous midinfrared absorption (mid-IR band), and interband transitions are discussed. The mid-IR band (band maximum [omega][sub [ital m]][similar to]0.5 eV) is found to be similar to that observed in the isostructural materials La[sub 2[minus][ital x]]Sr[sub [ital x]]CuO[sub 4], and is identified with photon-assisted hopping of small polarons. A microscopic theory developed by Reik is used to obtain polaron parameters whose values are compared to those obtained similarly for other small-polaron materials.

• DOE Contract Number: FG02-90ER45427
• OSTI ID: 6351224
• Journal Information: Physical Review, B: Condensed Matter; (United States), Journal Name: Physical Review, B: Condensed Matter; (United States) Vol. 48:5; ISSN PRBMDO; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360207* -- Ceramics
Cermets
& Refractories-- Superconducting Properties-- (1992-)
ABSORPTION SPECTRA
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
AMBIENT TEMPERATURE
CHALCOGENIDES
COPPER COMPOUNDS
CORRELATIONS
CRYSTAL DOPING
CUPRATES
ENERGY RANGE
HIGH-TC SUPERCONDUCTORS
INFRARED SPECTRA
KRAMERS-KRONIG CORRELATION
LANTHANUM COMPOUNDS
LANTHANUM OXIDES
NICKEL COMPOUNDS
NICKEL OXIDES
OPTICAL PROPERTIES
OXIDES
OXYGEN ADDITIONS
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
POLARONS
QUASI PARTICLES
RARE EARTH COMPOUNDS
SPECTRA
STRONTIUM ADDITIONS
STRONTIUM ALLOYS
STRONTIUM COMPOUNDS
STRONTIUM OXIDES
SUPERCONDUCTORS
TEMPERATURE DEPENDENCE
TRANSITION ELEMENT COMPOUNDS