Dynamic Electrical Pathway Tuning in Neuromorphic Nanowire Networks

Neurobiology-inspired phenomena such as winner-takes-all competition and critical dynamics have been recently reported to arise in neuromorphic nanowire networks. These are unique systems where interactions between memristive elements creates emergent conductance pathways between discrete electrodes. This mode of operation can offer substantial advantages to create a truly concomitant plastic-static system for integration in neuromorphic devices. However, critical aspects such as pathway controllability and stability are yet to be explored. In this study, pathway formation in self-assembled neuromorphic networks formed by Ag nanowires decorated with TiO(2)nanoparticles is investigated. Direct visualization of pathway formation through a neuromorphic network is attained using the lock-in thermography technique. Using this technique, it is demonstrated that how networks preserve information from previously used pathways through increased local junction connectivity. This effect directly reshapes subsequent formation of pathways whenever the spatial location of the electrodes is dynamically changed. Combining these results with conventional current-voltage measurements, which show that the network electrically acts as a volatile switching memristor, a unique interaction between short-term and long-term memory arises. This produces unexpected collective dynamical states of potentiation and inhibition of network conductance whenever different spatiotemporal signals are dynamically fed to the network.