FRACTAL DIMENSIONS FROM CHAOTIC OSCILLATIONS IN SEMIINSULATING GAAS

Relaxation and domain current oscillations in undoped semi-insulating GaAs were observed at room temperature for a broad range of voltage ap plied to a sample. The oscillations were characterized by a reconstruc tion of an attractor of the system. An analysis of the attractor helpe d to discriminate between the two types of oscillations. A transition from one type of oscillations to the other was connected with a chaoti zation of the current. A chaotic state of the system was analyzed by c alculations of fractal dimensions D(q) for -0.6 < q < 40 and the f(alp ha) function.