We calculate the temperature dependence of the infrared frequencies of the TO and LO modes with the symmetries of A(1), B-1 and B-2 mainly in the ferroelectric phase of NaNO2. This calculation is carried out using the ...

The temperature dependence of the phonon frequency omega(ph) and of the damping constant Gamma(sp) due to pseudospin-phonon coupling of the lowest-frequency soft mode is calculated in the ferroelectric phase near the ...

We calculate the order parameter (spontaneous polarization) and the inverse dielectric susceptibility at various temperatures in the ferroelectric phase of LiNbO3 for its ferroelectric-paraelectric phase transition (T-C ...