Results 271 to 280 of about 82,121 (307)
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On the infrared activity of soft modes
Physics Letters A, 1974Abstract The relation between the soft-mode infrared activity and proper, improper and non-ferroelectricity is discussed. The soft mode can be infrared active in the distorted phase even at non-ferroelectric transitions. The dielectric anomaly in these cases is also discussed.
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Philosophical Magazine B, 2001
Abstract The concept of atomic soft modes in glass dynamics and general assumptions and some basic results of the soft-mode dynamics theory of glasses are discussed in the light shed by experimental observations. Negative- U centres as actual electronic mobility-gap centres, vast pressure-induced effects in dynamics, quasilinear frequency dependence of
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Abstract The concept of atomic soft modes in glass dynamics and general assumptions and some basic results of the soft-mode dynamics theory of glasses are discussed in the light shed by experimental observations. Negative- U centres as actual electronic mobility-gap centres, vast pressure-induced effects in dynamics, quasilinear frequency dependence of
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1980
There has been great interest over the last decade in pseudo one and two dimensional crystals. While remaining relatively isotropic acoustically, these systems frequently exhibit phase transitions, sometimes accompanied by soft modes, due to the highly anisotropic electron phonon interaction.
J. D. N. Cheeke, D. Houde, N. K. Hota
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There has been great interest over the last decade in pseudo one and two dimensional crystals. While remaining relatively isotropic acoustically, these systems frequently exhibit phase transitions, sometimes accompanied by soft modes, due to the highly anisotropic electron phonon interaction.
J. D. N. Cheeke, D. Houde, N. K. Hota
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Physical Review Letters, 1969
The self-consistent phonon formalism, successful in the description of the quantum crystals ${\mathrm{He}}^{3}$ and ${\mathrm{He}}^{4}$, is here applied to a discussion of the soft $k=0$ TO mode in SnTe. Straightforward considerations allow us to arrive at a simple expression for $\ensuremath{\omega}_{\mathrm{TO}}^{}{}_{}{}^{2}(k=0)$ in the low ...
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The self-consistent phonon formalism, successful in the description of the quantum crystals ${\mathrm{He}}^{3}$ and ${\mathrm{He}}^{4}$, is here applied to a discussion of the soft $k=0$ TO mode in SnTe. Straightforward considerations allow us to arrive at a simple expression for $\ensuremath{\omega}_{\mathrm{TO}}^{}{}_{}{}^{2}(k=0)$ in the low ...
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Superconductivity and soft modes in CdS
Zeitschrift f�r Physik B Condensed Matter, 1987We show that adequate superparacurrent is induced by a magnetic field in an insulator provided soft modes can be identified at the edge of a zone, and there is strong unsymmetric electron-phonon coupling. It is thought that this analysis is relevant to the situation in CdS, where correlation between the occurrence of soft modes and unusual magnetic ...
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Journal of the Physical Society of Japan, 1973
The spin-wave theory is developed for the study of the acoustic soft-magnon modes in hematite (α-Fe 2 O 3 ). The energies ω 0 of the soft-modes are approximately given as ω 0 ∞| T M - T | 1/2 near the Morin phase transition temperature T M and the results are compared with the AFMR experiments.
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The spin-wave theory is developed for the study of the acoustic soft-magnon modes in hematite (α-Fe 2 O 3 ). The energies ω 0 of the soft-modes are approximately given as ω 0 ∞| T M - T | 1/2 near the Morin phase transition temperature T M and the results are compared with the AFMR experiments.
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Soft acoustic modes in trigonal crystals
Physical Review B, 1985, Terhune, , Kushida, , Ford
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