Polymorphic signal responses of phase-change quantum dot string upon stochastic resonance

We successfully constructed phase-change quantum dots string (PCQDS) systems and studied their signal responses. The PCQDS actually is a cascaded structure consisted of several stochastic resonance (SR) two-state systems, in which inherent non-linearity, i.e., phase-change of quantum dots (QDs), plays elementary and important roles to modulate signal output. We established an SR model to simulate signal responses depending on stimulation history. We know that some QDs will oscillate with input forcing frequency, while certain QDs will oscillate in their own frequency triggered by phase transition. These two effects cooperate to generate polymorphic response patterns, including action potential patterns exhibited by envelope of spike peak values. An interesting and important simulation is that we replicate the memory effect in Nb-doped AlNO, i.e., a QDs dispersed system. The result indicates that memory can occur in a system only constructed by volatile elementary units, implying memory existing in network. Long-term plasticity and spike-rate dependent plasticity can also be realized by using frequency and phase modulation. Our study provides a new scope to study signal handling and memory effect in quantum system.