Unraveling the Atomic Redox Process in Quantum Conductance and Synaptic Events for Neuromorphic Computing

Manipulation of atomic point contact (APC) in memristive devices is considered as an essential approach in emulating biological synaptic functions and paves the way for developing neuromorphic computing systems. In this article, the conductance modulation in a polyvinylimidazole (PVI)-based memristor that mimics the synaptic functions underlying the sensory memory, short-term memory, long-term memory, and forgetting events of the human brain, is demonstrated. A detailed analysis of resistive switching, quantum conductance, and synaptic behaviors in the silver (Ag) included PVI memristor is investigated by means of DC sweep and pulse current-voltage (I-V) measurements. Based on the synaptic plasticity of the Ag-PVI memristor, the biological synaptic functions such as learning and forgetting two images are mimicked using 5 x 5 synaptic memristor arrays. To explain the relationship between the atomic redox process and synaptic events in the memristor, the I-V/cyclic voltammetry study is introduced. As a consequence, the concentration of charges in the APC region increases as the conductance state increases. This study is essential in order to explore the progressive growth of APC under confined redox reaction in the electrochemical metallization-based memristors for developing both synaptic devices and high-density multilevel memories.