Deterministic chaos in acoustoelectric systems

The paper has predicted, experimentally observed, and explained deterministic chaos or strange attractor in acoustoelectric systems. Experiments were carried out in systems based oil layered piezoelectric-semiconductor structure, YZ-LiNbO₃/n-Si. Ther were created conditions for self-sustained oscillations of transverse acoustoelectric voltage (TAV) under propagating surface acoustic waves (SAW). Several bifurcations have been studied under pump SAW signal increasing. For small pump SAW signal the system was not oscillating and there were no TAV self-oscillations. When the pump signal was sufficiently large, steady TAV self-oscillations were occurred in the frequency range up to several kHz. Phase portrait of the TAV signal was a closed loop, a steady attractor. Its power spectrum had basic and multiple harmonics. As the pump signal was further increased, the TAV self-oscillations became unsteady for some semiconductors. The phase portrait was not only the steady closed loop. A steady attractor and an unsteady, strange, attractor were occurred. The power spectrum did not have a few harmonics, it became continues. The chaotic TAV was not shown to be a random noise. It has been established that the way in which the behaviour of the system became chaotic was a intermittancy that is one of the roads to the deterministic chaos or stochastic self-oscillations, strange attractor. A phenomenological theory explaining the experiments has been presented