Non-stationary and relaxation processes and induced microscale polar regions in incommensurate phase of ferroelectric semiconductor Sn2P2Se6

For the ferroelectric (FE) semiconductor Sn2P2Se6 which has the incommensur ate phase (ICP) the study of temperature and time behaviour of pyroelectric , ferroelectric and dielectric parameters, current-to-voltage and transient current characteristics, non-stationary and memory effects was performed. Longterm low-frequency (10 Hz - 1 kHz) electric oscillations appear in a de ep ICP and acquire the relaxation character in the vicinity of ICP-FEP tran sition. No less than three main frequencies in the oscillation spectrum are observed. Transition to the stochastic regime and subsequent transition to the space-time organization processes are discussed. Theoretical considera tion based on the suggestion that the evolution of the local states of the system represents a self-organizing process is performed. The main peculiar ity of ICP-FEP transition is the coexistence of incommensurate and fine-dom ain structures with initial zero degree of unipolarity, The main peculiarit y of FEP-ICP transition after being in a deep FEP is the existence of mixed polar-incommensurate state in the ICP.