“…This temperature behavior is in qualitative agreement with the experimental data [6,7,12]. Recently, Hasegawa et al [27] have obtained a clear anomaly in the temperature dependence of the specific heat at T = 305 K. It was clarified that the temperature dependence of the order parameter associated with this new phase transition at 305 K is quite similar to those of spontaneous polarization reported previously for example by Ikeda et al [6]. Without electron-phonon interaction the maximum and the plateau are much smaller (curve 2) what shows the importance of the electron-phonon interaction.…”