The influence of the magnetic field on the dynamics in superlattices

摘要

We theoretically investigate the influence of external magnetic fields on current oscillations in weakly coupled GaAs/Al_xGa_(1-x)As superlattices when the system is driven by a pure DC voltage. The formation of unstable electric-field domains under the action of a small magnetic field indicates the current oscillation occurs in superlattices. Increasing magnetic fields, the stationary electric-field domain is created and current oscillations disappear. Thus, the system state is transferred from dynamic to stationary by the control of magnetic fields. When the system is subject to an AC voltage in the presence of small magnetic fields, a variety of nonlinear behaviors are obtained due to the coupling between the internal oscillations and external signals.