Variation of spectral properties of dielectric ionic crystal in the terahertz range due to the polariton absorption

Abstract

The dispersion equations for polariton waves in dielectric ionic crystal with the absorption are obtained. The self-consistent solutions of the system of Maxwell electromagnetic field equations and the equations of motion of ions have been used. The elastic and absorption properties of the crystal are taken into account in the ion equations of motion. It is shown that the separated equations of motion for positive and negative ions allow obtaining all branches of phonon and polariton spectrum by the example of the ionic crystal of cubic symmetry at the terahertz range. It has been shown that the variation of absorption in the crystal leads to changing of the character of spectrum branch and the polariton velocities.

The role of terahertz polariton absorption in the characterization of crystalline iron sulfate hydrates

“…Recently, a method for solving the dispersion relationship for polariton waves was reported by Dzedolik and Pereskokov using classical mechanics and then applied to cubic crystal systems. 63 While promising, the FeSO 4 Á7H 2 O solid investigated here is of significantly larger size and lower symmetry compared to the cubic systems, and the application of this method is unfortunately not immediately feasible. Despite the challenges associated with the rigorous calculation of polariton absorption in FeSO 4 Á7H 2 O, the available evidence strongly suggests this to be the origin of the broad absorption feature centered at 36.90 cm À1 .…”