Random acoustoelectric oscillations of current in piezoelectric semiconductors

The effect of the supersonic drift of charge carriers on phonon generation in tellurium crystals is studied under the conditions of the emergence of a coustic instability leading to dynamic chaos. All stages of the stochastici ty evolution are traced experimentally with varying the external conditions , namely, the magnitude of the static electric field, determining the drift of charge carriers, and the magnitude and direction of the magnetic field. It is shown that with increasing electric and magnetic fields, the periodi c oscillations of the current are transformed into random oscillations thro ugh the frequency-doubling and tripling bifurcations. A mathematical model in the form of phase trajectories of the dissipative dynamic system and the spectral portraits corresponding to transient processes are described. (C) 2001 MAIK "Nauka/Interperiodica".