INFRARED EVIDENCE FOR THE COEXISTENCE OF FREE AND BOUND CHARGES IN Nd2-xCexCuO4 AND Bi2Sr2CuO6

Electron-doped Nd 2-x Ce x CuO 4 and hole-doped Bi 2 Sr 2 CuO 6 have been studied in the infrared to discriminate between the existing models of the optical conductivity σ(ω) in metallic cuprates. In Nd 2-x Ce x CuO 4 an absorption peak clearly visible in the insulating phase softens for increasing x and for decreasing temperature, until it reaches the far infrared (FIR peak) at the insulator-to-metal transition. In the superconducting phase it persists beside the free-carrier Drude absorption, as shown by fitting procedures, and disappears only in the overdoped normal metal. Direct evidence for the presence of the FIR peak in a metallic cuprate comes from the reflectivity of a Bi 2 Sr 2 CuO 6 film, measured down to 10 cm -1, where we could resolve the FIR peak from a normal Drude term as narrow as 35 cm -1 at low T. This observation provides direct evidence for the coexistence of free and "bound" charges in a superconducting cuprate.

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Free-carrier dynamics in Au2Pb probed by optical conductivity measurements

Journal of Physics Condensed Matter ◽

10.1088/1361-648x/aae7b1 ◽

2018 ◽

Vol 30 (48) ◽

pp. 485403 ◽

Cited By ~ 1

Author(s):

R Kemmler ◽

R Hübner ◽

A Löhle ◽

D Neubauer ◽

I Voloshenko ◽

...

Keyword(s):

Optical Conductivity ◽

Free Carrier ◽

Carrier Dynamics ◽

Conductivity Measurements

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Free-carrier absorption in Be- and C-doped GaAs epilayers and far infrared detector applications

Journal of Applied Physics ◽

10.1063/1.1347002 ◽

2001 ◽

Vol 89 (6) ◽

pp. 3295-3300 ◽

Cited By ~ 30

Author(s):

A. L. Korotkov ◽

A. G. U. Perera ◽

W. Z. Shen ◽

J. Herfort ◽

K. H. Ploog ◽

...

Keyword(s):

Infrared Detector ◽

Far Infrared ◽

Free Carrier ◽

Free Carrier Absorption ◽

Carrier Absorption

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Determining the Free Carrier Density in Cd x Hg1–xTe Solid Solutions from Far-Infrared Reflection Spectra

Semiconductors ◽

10.1134/s1063782617130048 ◽

2017 ◽

Vol 51 (13) ◽

pp. 1732-1736

Author(s):

A. G. Belov ◽

I. A. Denisov ◽

V. E. Kanevskii ◽

N. V. Pashkova ◽

A. P. Lysenko

Keyword(s):

Solid Solutions ◽

Carrier Density ◽

Far Infrared ◽

Free Carrier ◽

Reflection Spectra ◽

Free Carrier Density ◽

Infrared Reflection

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Primary Odors and Insect Attraction

The Canadian Entomologist ◽

10.4039/ent981083-10 ◽

1966 ◽

Vol 98 (10) ◽

pp. 1083-1093 ◽

Cited By ~ 12

Author(s):

R. H. Wright

Keyword(s):

Statistical Analysis ◽

Absorption Spectra ◽

Infrared Absorption ◽

Direct Evidence ◽

Far Infrared ◽

Vibrational Frequencies ◽

Insect Attractants ◽

Single Substance ◽

Insect Attraction ◽

Infrared Absorption Spectra

AbstractA statistical analysis of U.S.DA. studies of insect attractants provides the first direct evidence for the reality of "primary" odors (heretofore inferred indirectly from abstract principles). Molecules of a single substance may carry more than one primary osmic character and the presence of one does not preclude another, but some primaries may overlap others. Thus the molecular qualities responsible for osmic properties appear to be distributed along a continuum. Molecular vibrational frequencies are so distributed, and the far infrared absorption spectra of some attractant and non-attractant substances show correlations of the sort predicted by the theory.

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Far-infrared magnetooptical generalized ellipsometry determination of free-carrier parameters in semiconductor thin film structures

MRS Proceedings ◽

10.1557/proc-744-m5.32 ◽

2002 ◽

Vol 744 ◽

Cited By ~ 1

Author(s):

Tino Hofmann ◽

Marius Grundmann ◽

Craig M. Herzinger ◽

Mathias Schubert ◽

Wolfgang Grill

Keyword(s):

Hall Effect ◽

Dielectric Function ◽

Far Infrared ◽

Free Carrier ◽

Independent Experiment ◽

Electron Mass ◽

Effective Electron Mass ◽

Effective Electron ◽

Infrared Wavelengths

ABSTRACTIn accord with the Drude model, the free-carrier contribution to the dielectric function at infrared wavelengths is proportional to the ratio of the free-carrier concentration N and the effective mass m*, and the product of the optical mobility μ and m*. Typical infrared optical experiments are therefore sensitive to the free-carrier mass, but determination of m* from the measured dielectric function requires an independent experiment, such as an electrical Hall-effect measurement, which provides either N or μ. Highly-doped zincblende III-V-semiconductors exposed to a strong external magnetic field exhibit non-symmetric magnetooptical birefringence, which is inversely proportional to m*. If the spectral dependence of the magnetooptical dielectric function tensor is known, the parameters N, m* and μ can be determined independently from optical measurements alone. Generalized ellipsometry measures three complex-valued ratios of normalized Jones matrix elements, from which the individual tensor elements of the dielectric function of arbitrarily anisotropic materials in layered samples can be reconstructed. We present the application of generalized ellipsometry to semiconductor layer structures at far-infrared wavelengths, and determine the magnetooptical dielectric function for n-GaAs and n-AlGaInP for wavelengths from 100 μm to 15 μm. We obtain the effective electron mass and mobility results of GaAs in excellent agreement with results obtained from Hall-effect and Shubnikov-de-Haas experiments. The effective electron mass in disordered n-AlGaInP obtained here is in very good agreement with previous k·p calculations. (Far)-infrared magnetooptic generalized ellipsometry may open up new avenues for non-destructive characterization of free-carrier properties in complex semiconductor heterostructures.

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