# dielectric permittivity

## Frequency spectrum of surface plasmon-polariton waves: influence of Coulomb correlations

The model that describes the influence of Coulomb interaction between electrons (Coulomb correlations) on a frequency spectrum of plasmon-polariton waves in electroneutral structures dielectric/metal/dielectric is investigated.  It is shown that for atomically thin metal films (ATMF), such correlations affects both the quantum-dimensional behavior of the frequency spectrum as a function of the thickness of the metal film and
significantly improves the correlation of theoretical calculations and experiment.

## Influence of uniaxial and hydrostatic pressures and shear stress $\sigma_{5}$ on the phase transition and thermodynamic properties of quasi-one-dimensional ferroelectrics of the CsH$_2$PO$_4$ type

Within the framework of the modified proton ordering model for the quasi-one-dimensional hydrogen bonded ferroelectrics of the CsH$_2$PO$_4$ type with taking into account the linear in the strains  $\varepsilon_1$, $\varepsilon_2$, $\varepsilon_3$, and $\varepsilon_5$ contributions into the energy of the proton subsystem, without tunneling, using the two-particle cluster approximation, we study the influence of uniaxial pressures $p_{i}$, hydrostatic pressure $p_{h}$, and shear stress $\sigma_{5}$ on the phase transition, polarization, transverse dielectric permittivity, elastic constants a

## Influence of the electroneutrality of a metal layer on the plasmon spectrum in dielectric-metal-dielectric structures

In this paper, we propose a model that allows us to investigate the influence of quantum size effects and the electroneutrality condition on the spectrum of SPPs waves as a function of metal thickness in heterogeneous dielectric/metal/dielectric structures.  It is shown that for ultrathin metal layers, the spectrum of plasmon waves has oscillatory behavior in the domain of small wave vectors  (k~0.05-0.2 1/nm).  The amplitude of oscillations depends on the conditions of electroneutrality for the dielectric/metal/dielectric structure.

## Surface plasmon polaritons in dielectric/metal/dielectric structures: metal layer thickness influence

A model is proposed and studied that makes it possible to explain experimental data on a metal layer thickness influence on  the spectrum of SPPs waves in heterogeneous dielectric/metal/dielectric structures.