Controle de caos em amostras semi-isolantes de arseneto de gálio

Abstract

Low frequency current oscillations have been usually investigated under the influence of the external applied bias, the temperature and the illumination. A parallel applied magnetic field has been used in the present work in order to obtain odd periodic windows and bifurcations inside them in a two dimension parameter space in a semi-insulating GaAs grown by molecular beam epitaxy. Two kinds of parameter spaces have been used in order to stabilize the odd periodic windows and the bifurcations, namely, the external applied bias versus the parallel magnetic field and the illumination versus the parallel magnetic field. We report on a successful observation of stable cycles of periodicity 3, 4, 5, 6, 7 and 8 inside a period-3 window. An example of bifurcation route is presented following the sequence from chaos to 4, 3, 6, 3, 5, 7, 5, and back to chaos in the parameter space of bias versus magnetic field. In this bifurcation route we will show which branch of the cycle is bifurcating and which are coalescing.