Bifurcation diagram, noise reduction and period-four cycle on low frequency current oscillations in a semi-insulating GaAs sample

Low frequency oscillations (LFO) on current I(V, t) curves were studied in a GaAs sample grown by molecular beam epitaxy. Our measurements were carried out at a temperature of 200 K and under infrared illumination. The nonlinear I(V) characteristics give rise to spontaneous oscillations under constant applied bias V. The attractors were constructed by the delay vector technique with the delay value given by minimal mutual information. A bifurcation diagram was constructed from the minima sequence as a function of the applied bias. A noise reduction algorithm applied to the raw data allowed the cleaning of the bifurcation diagram. We have identified a bifurcation route of periodicity following the sequence 0–1–2–4–2–∞ having the applied bias as the control parameter. Fourier transforms is a merit figure of the noise reduction procedure and also a qualitative proof of the chaotic regime.