Electrical and pyroelectric properties of TIInS2

Abstract

Abstract A number of phase transformations of different character was found to occur in TlInS2 single crystals at temperatures from 170 to 220 K.1–6 Using submillimeter BWT spectrsocopy method, the transition of TlInS2 to the ferroelectric phase was first found to appear at T = 189 K, and a special feature was observed in the temperature dependence of the dielectric constant near T = 213 K. The existence of ferroelectric and incommensurate phase transitions in TlInS2 was confirmed in2–4 (Table I). From investigations of the fundamental absorption edge, it was found that in the temperature region of 165–225 K the four phase transitions take place in TlIS2 (Table I). When studying the electrical properties and electroabsorption in TlInS2 at low temperatures the energy gap of TlInS2 (2.2 eV) was determined in.7–9 The current carriers scattering on acoustic phonons was observed, and the structure attributed to exciton transition was revealed in electroabsorption spectra. The effect of phase transitions on the electrical properties and electrical absorption was not observed in.7–9 Based on the mentioned above, the present paper deals with the results of studying the pyroelectrical and electrical properties of TlInS2 at low-temperature phase transitions.