Physico-Chemical nanomaterials science
Influence of the In-Ga substitution on the physical properties of layered CuInP2S6 crystals
H. Ban, D. Gal, A. Haysak, A. Molnar
Department of the Physics of Semiconductors, Uzhhorod National University, Voloshina Str. 54, Uzhhorod, 88000, Ukraine
E-mail: alexander.molnar@uzhnu.edu.ua
Layered crystals of the Me1Me2P2S6 family are promising 2D functional materials for nanoelectronics. One of the most interesting of them is CuInP2S6 and solid solutions based on it. 
We investigated the temperature dependence of the dielectric constant of 80%CuInP2S6- 20%CuGaP2S6 solid solution in the temperature range 80-450 K and the frequency range 10÷105 Hz. To determine the potassium content, we used the method of extraction-photometric determination [1]. As can be seen in Figure 1, the phase transition temperature for this composition is 318K, which is 3 degrees higher than that of a pure crystal CuInP2S6. At temperatures below 200K (more precisely, at 120-140K at 10 kHz), a "step" is observed on the temperature dependence of the real part of the dielectric constant, and a maximum on the temperature dependence of the imaginary part of the dielectric constant. Such dielectric dispersion is typical for dipolar glasses.

Fig. 1. Temperature dependency of real a and imaginary b parts of complex dielectric permittivity ε*= ε’-i·ε” of 80%CuInP2S6- 20%CuGaP2S6 solid solution.

1.	Воронич О.Г., Савко Н.І. Екстракційно-фотометричне визначення галію // Науковий вісник Ужгородського університету. Серія Хімія. – 2016. - 36, C.50-52