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

Abstract

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.