0372-400Х (Edition in Ukrainian)
2071-0186 (Edition in English)
2071-0194 (in electronic form)
Abbreviated key title: Ukr. J. Phys.
Oles Honchar Dnipropetrovsk National University
(72, Gagarin Ave., Dnipropetrovsk 49050, Ukraine; e-mail: email@example.com)
Frequencies of Long-Wave Phonon-Polaritons and Optical Phonons in Diatomic Ionic Crystals
Section: Solid matter
Original Author's Text: Ukrainian
Abstract: Long-wave phonon-polaritons and longitudinal optical phonons in ionic crystals with two atoms per unit cell have been considered. The model of the point charge and the self-consistent electromagnetic field in the dielectric medium is used. The standard dispersion laws for both branches of phonon-polaritons regarded as transversal waves are obtained. The frequency of longitudinal optical phonons is expressed in terms of the ion plasma frequency in an insulator multiplied by the factor √ε0/ε0-ε∞, where ε0 is the static dielectric constant, and ε∞ is the high-frequency one. A good agreement between the found expression and tabulated data is found.
Key words: ionic crystal, self-consistent electromagnetic field, long-wave vibrations, phononpolaritons, longitudinal optical phonons, ion plasma frequency.