Chaos and hyperchaos in the electric avalanche breakdown of p-germanium at 4.2 K

Abstract

p-Ge electrically driven into the post-breakdown regime at 4.2 K produces spontaneous current oscillations. Under variation of the control parameter, namely the electric or magnetic field, we observed different routes to chaos, and a transition from a chaotic to a hyperchaotic state. Simultaneously, a loss of spatial coherence was found, indicating a break-up of the system in coupled subsystems. Phonons seem to be an important coupling mechanism between these subsystems.