Analysis of infrared reflectivity in the presence of asymmetrical phonon lines

Servoin, J. L.; Gervais, F.

doi:10.1364/ao.16.002952

Cited by 18 publications

(8 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the metallic binding in HgTe is mani-fested by an anomalous temperature dependence of the HgTe vibrational modes. As temperature increases from 8 to 300 K, the optical mode frequency increases from 117 to 119 cm Ϫ1 , 29 and the mode frequency of the Cd͑1͒Hg͑3͒Te basis cell increases by 2 cm Ϫ1 . However, the Hg-Te mode of the Cd͑3͒Hg͑1͒Te cell behaves like an ordinary semiconductor mode; its frequency decreases from 131 to 128 cm Ϫ1 as temperature increases.…”

Section: A Lattice Modes Of Cd-te and Hg-te Vibrationsmentioning

confidence: 99%

Structural analysis of the semiconductor-semimetal alloyCd1−xHgxTeby infrare

1998

View full text Add to dashboard Cite

Far-infrared reflectivity measurements have been made on traveling-heater-method-grown Cd 1Ϫx Hg x Te bulk single crystals. The spectra at 300, 77, and 25 K display two bands with fine structure, which cannot be explained by the usual two-oscillator model. These lattice spectra are shown to originate from four Cd-Te and Hg-Te vibrational modes in five basic Cd(4Ϫn)Hg(n)Te (nϭ0,1,2,3,4) cells consisting of cations tetrahedrally distributed around a shared Te anion. The mode frequencies are determined by the cation configuration in each cell. They are assumed to be independent of alloy composition, which determines only the mode strengths. The temperature dependence of the Cd-Te and Hg-Te vibrations revealed differences. The Cd-Te frequencies decrease with temperature, as is typical for semiconductor compounds. For the Hg-Te vibrations the temperature dependence is more complicated. Such temperature behavior was explained by influence of the anharmonicity corrections, which change sign with variation of frequency. Dispersion analysis of the dielectric function Љ(w) restored from the reflection spectra of the alloys at 25 K by Kramers-Kronig analysis revealed a peculiarity at 137 cm Ϫ1 , which appears with nearly constant strength over the wide compositional range x ϭ0.1-0.8. This mode has the same temperature dependence as the Cd-Te vibrational modes. The most probable explanation of this mode is associated with the alloy disorder or with multiphonon processes.

show abstract

Section: A Lattice Modes Of Cd-te and Hg-te Vibrationsmentioning

confidence: 99%

Structural analysis of the semiconductor-semimetal alloyCd1−xHgxTeby infrare

1998

View full text Add to dashboard Cite

show abstract

“…[5][6][7][8][9] These vibrational properties of CLN and CLT have been investigated by various experimental methods including Fourier transform infrared (FT-IR) and Raman spectroscopy. 8,[10][11][12][13][14][15][16] CLN and CLT have the congruent composition with the ratio of [Li]/[Nb] and [Li]/[Ta] of about 0.95, 17) because of their intrinsic defects, and single crystals of CLN and CLT are usually grown by the conventional Czochralski method.…”

Section: Introductionmentioning

confidence: 99%

Terahertz time-domain spectroscopy of congruent LiNbO₃ and LiTaO₃ crystals

Igawa

Mori

Kojima

2014

Jpn. J. Appl. Phys.

View full text Add to dashboard Cite

The complex dielectric constants of congruent LiNbO3 and LiTaO3 single crystals in a THz frequency region have been determined directly by using broadband terahertz time-domain spectroscopy (THz-TDS) with reflection configuration. We have successfully extracted the accurate complex dielectric constants by using corrected phase information derived from the transmission measurement results. The lowest E(TO1) phonon modes of both crystals have been observed clearly. On the other hand, additional bands at approximately 2.5 THz below the lowest A 1(TO1) mode frequency have been observed. These bands have also been reported by Raman and hyper-Raman spectroscopy and attributed to intrinsic defects in congruent crystals. According to the experimental results that these additional bands were observed at almost the same frequency on Raman, hyper-Raman, and THz-TDS, these bands are suggested to be assigned as a first-order scattering process.

show abstract

“…Several single crystals cut parallel or perpendicular to the FE axis from boules grown by the Czochralski pulling technique were used. The same authors [9][10][11] later performed a complete study of the temperature dependence of infrared reflectivity, including both sides of the ferroelectric-paraelectric (FE-PE) phase transition, with a modem Fourier-transform infrared spectrometer. Complementary transmission measurements performed on 30-and 147-/xm-thick thin slabs made use of a Michelson interferometer.…”

mentioning

confidence: 99%

“…E~H ~LO-~~ + i~'jro~O (2) was preferred by others [7][8][9][10][11]. Here the index LO refers to longitudinal optic modes.…”

mentioning

confidence: 99%

“…Data are given for the electric field of infrared radiation polarized perpendicular to the crystal c-axis (ordinary ray). This is why some authors [7][8][9][10][11] introduced a phonon self-energy function that yields in practice a frequency dependence of the damping function of certain modes (including the soft FE mode) to get a good fit to reflectivity data. The situation for the polarization parallel to the FE c-axis is more complicated.…”

mentioning

confidence: 99%

See 1 more Smart Citation