Investigations of phase transition dynamics in layered crystals by means of vibrational spectroscopy

Structural phase transitions in strongly anisotropic layered crystals are investigated by means of IR reflectance and Raman spectroscopies. We found a set of peculiarities in vibrational spectra, which are interpreted as being related to i) dramatic change of the phase transition order parameter near crystal surface in TIGaSe2; ii) slow fluctuations of the order parameter near Tc resulting in drastic change of shape of some vibrational bands; iii) an anomalous temperature dependence of the order parameter spatial fluctuations in mixed crystals TIGa(Se1-XSX)2.

Keywords:

• Vibrational spectroscopy
• layered crystals
• order parameter
• phase transition