Phase transitions and metastable states in TlGaSe₂

Abstract

The results of measurements of the dielectric constant of TlGaSe₂ in temperature range of successive phase transitions are presented. An anomaly in the temperature dependence of the real part of dielectric constant in TlGaSe₂ has been observed at about 242 K in addition to anomalies at 115, 108, and also near 65 K as reported in previous publications. The presence of temperature hysteresis effects in temperature interval between 115 and 242 K allowed making a conclusion about possible existence of an incommensurate phase in the mentioned temperature range. A model of succession of the structural phase transitions in TlGaSe₂ has been suggested.

Keywords:

• Ferroelectrics
• Dielectric constant
• Phase transitions

Acknowledgment

The authors are indebted to Research Projects Commission of Gebze Institute of Technology for supporting this work by the Grant No. 02-A-01-02-04.