External ac-signal-controlled dynamics of electric field domains in a GaAs/AlAs superlattice

The dynamics of the electric field domain of an ac-driven weakly coupled GaAs/AlAs superlattice is investigated. The ac-induced generation and annihilation of self-sustained current oscillations (SSCOs) is observed. The calculation using the discrete drift model based on a phenomenological drift velocity curve agrees well with the experimental observations. The localization of the domain wall at high ac frequencies is responsible for the disappearance of SSCOs. It indicates that the external ac signal is an additional important control parameter in the dynamics of weakly coupled superlattices besides the carrier concentration, sample temperature, and applied transverse magnetic field. (c) 2005 Elsevier Ltd. All rights reserved