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A. G. Milekhin Yu. A. Pusep Yu. A. Yanovskii V. V. Preobrazhenskii B. R. Semyagin D. I. Lubyshev 《JETP Letters》1996,64(5):393-397
The vibrational spectrum of short-period GaSb/AlSb superlattices in the frequency range of GaSb optical phonons is investigated
in detail. Localization of transverse GaSb optical phonons in GaSb/AlSb superlattices is observed experimentally for the first
time. The dispersions of TO and LO phonons in GaSb are measured.
Pis’ma Zh. éksp. Teor. Fiz. 64, No. 5, 361–364 (10 September 1996) 相似文献
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We have investigated the lattice vibrational properties of a two-component strained layer semiconductor superlattice (GaAs)
n1 (GaSb)
n2 using a one-dimensional linear chain model and transfer matrix method [1]. Effect of strain, arising due to the lattice mismatch
(∼ 7%) has been considered explicitly in the equation of motion. We show for the first time that the optical vibrational frequency
increases (in the case of (GaAs)4 (GaSb)
n
) or decreases (in the case of (GaAs)
n
(GaSb)4) with increase of layer thicknessn, in either type of superlattices. Raman scattering measurements on some other similar systems support our findings. 相似文献
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A. Milekhin T. Werninghaus D.R.T. Zahn Y. Yanovskii V. Preobrazhenskii B. Semyagin A. Gutakovskii 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,6(3):295-299
The vibrational spectrum of ultra-thin layer GaSb/AlSb superlattices was investigated in detail by infrared (IR) and Raman
spectroscopies. The effect of confinement of the transverse and longitudinal optical phonons in both types of the layers was
studied. The dispersions of optical phonons of the GaSb and the AlSb obtained from the analysis of the Raman and IR spectra
are in a good accordance with the theoretical data and results of neutron scattering experiments. First- and second-order
Raman spectroscopy indicates the presence of intermixture of atoms at the interfaces in the GaSb/AlSb superlattices.
Received: 11 May 1998 / Accepted: 21 July 1998 相似文献
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Barnas J 《Physical review. B, Condensed matter》1992,45(18):10427-10437
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Polariton electric fields and dispersion relations of some important complex-basis superlattices have been derived by means of electromagnetic theory and the Bloch's theorem. The spatial distribution of the polariton electric fields shows an interesting physical picture: the polaritons are mainly bulk modes as the wavenumber k is small and become typical interface modes with very strong peak intensities as k increases. 相似文献
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G.Gonzalez de la Cruz A. Tselis J.J. Quinn 《Journal of Physics and Chemistry of Solids》1983,44(8):807-812
Electronic collective modes in a semiconductor superlattice structure are studied within the self-consistent field approach. Plasmon and magneto-plasmon dispersion relations are obtained for the cases of strong and weak coupling between layers. The interaction of these collective modes with optical phonons is also investigated. 相似文献
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《Solid State Communications》1987,64(11):1383-1386
Phonon polariton modes in semiconductor superlattices are studied. Polariton electric fields and the dispersion relation are derived by electromagnetic theory, and due to periodicity in the direction normal to the superlattice layers, Bloch's theorem is applied. Polariton modes are found to exist between the TO and LO phonon frequencies, and approach the surface polariton frequency in the limit of large tangential wave vectors. The frequencies are also strongly dependent on the ratio of the layer thicknesses. Results are illustrated by a GaAsGaP superlattice. 相似文献
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M.J. Seong S. Francoeur S. Yoon A. Mascarenhas S. Tixier M. Adamcyk T. Tiedje 《Superlattices and Microstructures》2005,37(6):394-400
We have studied GaAs1−xBix (up to x3%) using Raman scattering with two different polarization configurations. Two Bi-induced phonon modes are observed at 186 cm−1 and 214 cm−1 with increasing Raman intensity as the Bi concentration increases. By comparing Raman selection rules for the observed Bi-induced phonon modes with those for the substitutional N vibrational mode (GaN mode) in GaAsN, the phonon mode at 214 cm−1 is identified as originating from substitutional Bi at the As site in GaAsBi. 相似文献
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《Surface science》1988,200(2-3):446-453
General dispersion equations for the magnetostatic modes in infinite and semi-infinite superlattices are derived by the transfer matrix method for the case of superlattices with an elementary unit consisting of N (N arbitrary) ferromagnetic layers. The films are assumed to be magnetized parallel to the film surfaces and parallel to an external magnetic field. Explicit forms of the dispersion equations, together with exemplary dispersion curves of surface modes and bands of bulk waves, are given in the case of N = 2. 相似文献
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《Superlattices and Microstructures》1987,3(4):371-377
We present a study of interface optical phonons and magnetostatic modes in semiconductor superlattices. We first review the propagation of longitudinal waves propagating parallel to the superlattice axis in order to show the similarities and differences between these and the interface modes just mentioned. The interface modes are discussed with the aim to interpret experiments carried out with superlattices of diluted magnetic semiconductors. 相似文献
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Calculations on long-wavelength lattice vibrations have been made for cystallline KNCS within the framework of the rigid ion model. The short range force constants and effective charges of the ions have been determined from the observed frequencies. Unobserved frequencies are predicted, and normal coordinates have been obtained and schematized. 相似文献
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The natural frequencies and distributions of displacement components for the surface vibrational modes in thin isotropic elastic disks are calculated. In particular, the research is focused on even solutions for low-lying resonant vibrations with large angular wave numbers. Several families of modes are found which are interpreted as modified surface modes of an infinitely long cylinder and Lamb modes of a plate. The results of calculation are compared with the results of the experimental measurements of vibrational modes generated by means of resonant excitation in duraluminum disk with radius of ≈90 mm and thickness of 16 mm in the frequency range of 130–200 kHz. An excellent agreement between the calculated and measured frequencies is found. Measurements of the structure of the resonant peaks show splitting of some modes. About a half of the measured modes has splitting Δfsplit/fmode at the level of the order of 10−5. The Q-factors of all modes measured in vacuum lie in the interval (2…3) × 105. This value is typical for duraluminum mechanical resonators in the ultrasonic frequency range. 相似文献
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A group-theoretical analysis of the vibrational spectrum of benzil crystals was carried out. The selection rules and normal coordinates were found. Raman scattering spectra of benzil single crystals were studied in polarized light within a broad temperature range from 100 K to the melting point (T m=96°C). The experimental data were found to correlate with theory. The temperature dependences of the spectral-line half-widths were used to separate the observed vibrations into translational and librational modes, and the correspondence between the experimentally observed vibrations and their normal coordinates was established in some cases. 相似文献
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《Superlattices and Microstructures》1986,2(4):297-301
We study bulk and surface collective modes in a metal superlattice using a formalism bringing out the classical nature of the excitations. Appropriate limits are investigated and earlier erroneous mode assignements for semiconductor superlattices are corrected. Explicit calculations are performed for a structure having metals of very different electron densities. Our study indicates that measuring the collective mode frequencies in superlattices can yield important geometrical information. 相似文献
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High-resolution terahertz absorption and Raman spectra of glutamine in the frequency region 0.2 THz-2.8 THz are obtained by using THz time domain spectroscopy and low-frequency Raman spectroscopy. Based on the experimental and the computational results, the vibration modes corresponding to the terahertz absorption and Raman scatting peaks are assigned and further verified by the theoretical calculations. Spectral investigation of the periodic structure of glutamine based on the sophisticated hybrid density functional B3LYP indicates that the vibrational modes come mainly from the inter-molecular hydrogen bond in this frequency region. 相似文献