Field-mediated Neural Transmission Within an Ag2S Gap-Type Atomic Switch

Unlike conventional synaptic transmission, biological field -mediated neural transmissions solely due to extracellular field effects are hardly emphasized in artificial synapse systems. Using an Ag2S gap -type atomic switch, we demonstrate the field -mediated transmission for low bias stimulations which is capable of generating measurable current due to pre -conditioning of the junction by a change in the electrochemical potential of ions prior to any precipitation. The observed current-voltage (I - V) characteristics for V < 100 mV are in good agreement with Simmon's tunneling model for asymmetric barrier (0) in the range 0 < V < Phi. For more than 100 consecutive voltage sweep cycles, an increase in hysteresis corresponding to an input energy of 10 - 1000 pJ was observed. The average barrier height was lowered from 1 eV to 0.125 eV and the effective mass of carrier electrons increased from 0.25 me to 2.5 me until the actual precipitation began. These results are of practical importance in developing artificial neural networks capable of mimicking field -mediated communications found in the cerebellum, heart, retina, and olfactory systems.