Chaotic dynamics in quantum-dot miniband superlattices

We have theoretically studied chaotic dynamics of ballistic electrons in Ga As-based quantum dot miniband superlattices under the influence of an inten se terahertz electromagnetic radiation, using the balance equations couplin g the self-consistent held equation. The electron motion that incorporates the influence of the self-consistent field within the miniband superlattice s produces a cooperative nonlinear oscillatory mode, which can lead to comp licated chaotic dynamics with the driving amplitude, driving frequency, and the relaxation frequency of the external circuit as the controlling parame ters. The temporal behaviors of the solutions of the nonlinear dynamical sy stem are analyzed by using different methods, such as phase portrait, power spectra, first return map, and Lyapunov exponent. The two-dimensional driv ing amplitude-frequency phase diagrams are calculated with a realistic trea tment of scattering contributions by impurity, acoustic phonon, and polar-o ptic phonons in order to visualize the chaotic regions in the parameter spa ce. The dependence of chaotic regions on the superlattice parameter, lattic e temperature, and external circuit condition, is extensively investigated, which provides useful guidance of controlling chaos in realistic device ap plications.