Far Infrared Study of the Copper Halides at Low Temperatures

Plendl, J. N.; Hadni, A.; Claudel, Jacques; Henninger, Y.; Morlot, G.; Strimer, P.; Mansur, L. C.

doi:10.1364/ao.5.000397

Cited by 76 publications

(30 citation statements)

References 8 publications

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“…The latter was observed in many papers, 1,2 but was mostly attributed to the impurity induced absorption. The only transmission measurements known to us were performed on pure CuCl, 30 where transmission was found to exhibit the maximum similar to one predicted in our paper. CuCl is a peculiar material, since Cu atoms at low temperature can occupy several non-equivalent positions, thereby creating internal defects.…”

Section: Discussionsupporting

confidence: 80%

Concept of local polaritons and optical properties of mixed polar crystals

Yamilov

Lisyansky

2000

Phys. Rev. B

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The concept of local polaritons is used to describe optical properties of mixed crystals in the frequency region of their restrahlen band. It is shown that this concept allows for a physically transparent explanation of the presence of weak features in the spectra of so called one-mode crystals, and for one-two mode behavior. The previous models were able to explain these features only with the use of many fitting parameters. We show that under certain conditions new impurity-induced polariton modes may arise within the restrahlen of the host crystals, and study their dispersion laws and density of states. Particularly, we find that the group velocity of these excitations is proportional to the concentration of the impurities and can be thousands of times smaller then the speed of light in vacuum. * Submitted to PRB To explain different types of behavior in mixed polar crystals, a number of theoretical models have been proposed. In the IR experiments, modes with wave numbers q ∼ 0 are excited. The Random Element Isodispacement model (REI) 17,18 takes advantage of this fact, assuming that the sublattices vibrate in phase with q = 0. With some modifications 3 after including the local field, and assuming a dependence of the force constants upon the composition, the modified REI model (MREI) was successfully used to fit two-mode crystals but encountered some problems in the one-mode materials. The fine structure of some mixed crystals was reproduced along the lines of REI by means of a considerable increase in the number of fitting parameters (cluster model 18 ). A different approach made use of the Green's function formalism in order to treat vibrations in the mixed crystals; averaging over disorder was performed either in a simple virtual crystal approximation (VCA) or with the use of the much more elaborate coherent potential approximation 19 (CPA). Interaction with the electromagnetic field in these approaches was included after the averaging procedure was performed. The mean field approximation treats the crystal as if it has atoms of the same sort with some average properties. It reproduces well the one-mode behavior, but could not possibly explain the two-mode systems. CPA combined with an electrostatic treatment of the electric field was used to fit a broader range of experimental data (see, for instance, Ref. 20).An important theoretical problem many researchers have focused upon is to find a simple criterion for different mode behavior, based upon dynamical properties of the crystals. Lucovsky 9 originally considered the significance of whether the original absorption bands overlap or not, which turned out to be a rather rough criterion. Harada and Narita 10 proposed a criterion based on relations between MREI constants (see also review papers in Refs. 1,2). It turned out that one-mode and two-mode crystals can be described using quite simple models with only a few fitting parameter, such as VCA and MREI, respectively. Lucovsky et al. in Ref. 9 made an attempt to establish a connection between the behavior...

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Section: Discussionsupporting

confidence: 80%

Concept of local polaritons and optical properties of mixed polar crystals

Yamilov

Lisyansky

2000

Phys. Rev. B

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“…In Ref.

ϵ_{normals} > 9

was concluded from infrared reflection spectroscopy (Fig. ) on a several μm‐thick film on quartz and a value

ϵ_{normals} = 15.1

is given in a table based on Kramers–Kronig analysis, however on a spectrally rather limited data set.…”

Section: Optical Properties Of Cuimentioning

confidence: 99%

Cuprous iodide - a p-type transparent semiconductor: history and novel applications

Grundmann

Schein

Lorenz

et al. 2013

Phys. Status Solidi A

241

313

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Halide semiconductors stand at the very beginning of semiconductor science and technology. CuI was reported as the first transparent conductor, and the first field effect transistor was made from KBr. Although halogens are frequently used in semiconductor preparation, little use is currently made from halide semiconductors in electronics and photonics. We review past reports on the metal halide semiconductor CuI and related alloys and discuss recent progress with regard to this material including its use in organic electronics and solar cells as well as our own work on fully transparent bipolar heterostructure diodes (p‐CuI/n‐ZnO) with high rectification of several 107 and ideality factors down to 1.5. γ‐CuI(111) thin film on glass (1 × 1 cm2) and IV‐characteristics of p‐CuI/n‐ZnO/a‐Al2O3 bipolar heterojunction diode.

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“…The far-infrared spectrum consists of two separate broad maxima centred at frequencies of about 0.8 and 3.0 THz, respectively. The low-frequency absorption band is not observed at room temperature as can be seen from the spectra of Plendl et al [13].…”

Section: Resultsmentioning

confidence: 88%

On the Local Motion of Cations in Solid Electrolytes: Far‐Infrared Spectra from β‐CuBr, Ag_0.85Cu_0.15Br, and AgBr

Börges

Eckold

Funke

1978

Ber Bunsenges Phys Chem

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The far‐infrared conductivity spectra of the fast ion conductor β‐CuBr (683 K), of the mixed crystal Ag0.85Cu0.15Br (573 K), and of AgBr (573 K) are experimentally determined from transmittance and reflectivity data. The very‐far‐infrared absorption band typical of structurally disordered solid electrolytes is observed in both β‐CuBr and Ag0.85Cu0.15Br. The band is interpreted in terms of a large‐amplitude irregular local motion of the cations. In the case of β‐CuBr, calculated frequency spectra are compared to the experimental conductivity.

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Far Infrared Study of the Copper Halides at Low Temperatures

Cited by 76 publications

References 8 publications

Concept of local polaritons and optical properties of mixed polar crystals

Concept of local polaritons and optical properties of mixed polar crystals

Cuprous iodide - a p-type transparent semiconductor: history and novel applications

On the Local Motion of Cations in Solid Electrolytes: Far‐Infrared Spectra from β‐CuBr, Ag_0.85Cu_0.15Br, and AgBr

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Far Infrared Study of the Copper Halides at Low Temperatures

Cited by 76 publications

References 8 publications

Concept of local polaritons and optical properties of mixed polar crystals

Concept of local polaritons and optical properties of mixed polar crystals

Cuprous iodide - a p-type transparent semiconductor: history and novel applications

On the Local Motion of Cations in Solid Electrolytes: Far‐Infrared Spectra from β‐CuBr, Ag0.85Cu0.15Br, and AgBr

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Product

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On the Local Motion of Cations in Solid Electrolytes: Far‐Infrared Spectra from β‐CuBr, Ag_0.85Cu_0.15Br, and AgBr