Chaotic Behavior of a Driven Current Filament Observed in High-Purity n-GaAs at 4.2 K

抄録

The chaotic response of a current filament formed by impact ionization of neutral shallow donors in high-purity n-GaAs has been investigated at 4.2 K under a dark condition. Stable hysteresis of the S-shaped current-voltage characteristic is perturbed externally by applying ac and dc voltages of the form of V_o+V_ac sin (2πf_ot). Bifurcation routes to chaos are investigated by varying V_o and f_o simultaneously, in the range of 2 V\lesssimV_o\lesssim3 V and 0.9 MHz\lesssimf_o\lesssim1.43 MHz, respectively. A period-doubling bifurcation, alternating period-chaotic bifurcation sequence and extrinsic crisis between two limit cycles are observed.