Experimental evidence for coherence resonance in a noise-driven GaAs/AlAs superlattice

Abstract

The presence of coherence resonance is experimentally identified in a doped, weakly coupled GaAs/AlAs superlattice (SL), which exhibits current self-oscillations when driven by noise. The physical mechanism is related to the interaction between the noise source and two oscillation modes of the SL oscillator: the well-to-well hopping mode and the dipole-motion mode. For a range of intermediate noise levels, the intrinsic oscillation mode of the SL oscillator, i.e. the well-to-well hopping mode, is activated, and the dipole motion is forced into a collective periodic oscillating state, resulting in coherence resonance.