Fluctuations of the Impurity Photoconductivity in Crystals of Cadmium Sulfoselenide Doped with Potassium: Nonequilibrium Thermodynamics and Mathematical Modeling

The results of the analysis of the fluctuations of the impurity photoconductivity in monocrystals of cadmium sulfoselenides doped with potassium upon their irradiation by impurity light via nonlinear nonequilibrium thermodynamics and mathematical modeling are presented. Based on nonlinear thermodynamics, it is established that the loss of stability of the system and the manifestation of critical phenomena are possible when autocatalytic stages and a negative feedback are implemented in the system under study. Based on the results of the qualitative analysis and numerical integration of the mathematical model, it is obtained that one stationary state of the “unstable focus” type is implemented; we conclude that the critical phenomena appear as a result of a bifurcation of the Andronov–Hopf type of a singular point to a limit cycle; it is shown that the proposed mathematical model satisfactorily describes the regularities of the manifestation of fluctuation effects.