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61.
The Raman scattering spectra of pure and mixed ammonium halide crystals are presented. A correlation between the halogen concentration in the samples and the frequency of the outer translational mode is shown. Experimental results and theoretical models are compared. 相似文献
62.
63.
The magnetic breakdown in metals is shown to cause the appearance of a new class of one-dimensional quasi-random “incommensurable” systems where the electrons are localized due to quantum interference effects. At this time both absolute localization and phase transition of “metal- dielectric” type can be realized. 相似文献
64.
V. S. Gorelik A. Yu. Pyatyshev A. S. Krylov 《Bulletin of the Russian Academy of Sciences: Physics》2016,80(9):1127-1130
Raman spectra of the ferroelectric sodium nitrite are recorded over a wide spectral range at different temperatures, including the ferroelectric phase transition interval. The room-temperature Raman spectrum reveals the overdamped А1(z) soft mode which is attributed to the ferroelectric phase transition. 相似文献
65.
Optical Raman spectra of a ferroelectric sodium nitrite crystal have been detected in a wide spectrum range at various temperatures, including the region of the ferroelectric phase transition. A manifestation of a transverse soft polar mode of the A 1(z) type responsible for the ferroelectric phase transition has been discovered in the spectrum at room temperature. This mode has been found to become overdamped even far from the ferroelectric phase transition temperature. This mode also appears as a central peak under heating. It has been found that the pseudoscalar mode of the A 2 type has the highest intensity in the Raman spectrum of sodium nitrite. The frequency corresponding to the maximum intensity of this mode in the Raman spectrum varies from 130 cm–1 at 123 K to 106 cm–1 at T = 513 K. A fair agreement of the experimental data for the A 1(z) mode with the Lyddane–Sachs–Teller relation has been established. The polariton curves for the A 1(z) polar mode and the dispersion curves for axinons has been plotted. 相似文献
66.
67.
A. Kadigrobov L. Y. Gorelik R. I. Shekhter M. Jonson 《Superlattices and Microstructures》1999,25(5-6):961-971
We use a semiclassical approach for analyzing the tunneling transport through a normal conductor in contact with superconducting mirrors. Our analysis of the electron–hole propagation along semiclassical trajectories shows that resonant transmission through Andreev levels is possible resulting in an excess, low-energy quasiparticle contribution to the conductance. The excess conductance oscillates with the phase difference between the superconductors having maxima at odd multiples of π for temperatures much below the Thouless temperature. 相似文献
68.
The conditions of parametric radiation generation on polaritons in cubic noncentrosymmetric crystals are studied. The possibility of such generation is theoretically justified. The polariton radiation frequencies are calculated for GaP, ZnSe, ZnTe, and GaAs crystals. The obtained generation frequencies are compared to the experimental results on Raman scattering on polaritons. The block diagram of the terahertz radiation generator operation using a GaP crystal and a pulsed laser with high peak power at low energy of laser pump pulses is presented. The lasing frequency shift is analyzed depending on the scattering geometry. The coefficient of exciting radiation conversion to the terahertz range is determined. 相似文献
69.
The results of the experimental study of the characteristics of stop bands of globular photonic crystals are presented depending of the globule diameter, temperature, and the presence of a dielectric medium in pores between globules. The reflectance spectra of the (111) surface of a globular photonic crystal are analyzed using a fiber-optic technique. As the sample temperature is lowered, the reflectance maximum shifts to the long-wavelength spectral region. The spectral characteristics of stop bands are compared with calculations based on the Wolf-Bragg formula. 相似文献
70.
M. A. Belyanchikov V. S. Gorelik B. P. Gorshunov A. Yu. Pyatyshev 《Journal of Experimental and Theoretical Physics》2017,124(1):77-84
High-Q librational modes have been found to be present in the infrared absorption and Raman spectra of chirally pure L-tyrosine. Such modes can serve as terahertz radiation detectors and generators in chirally pure biostructures. 相似文献