Reconfigurable Low-Power TiO2 Memristor for Integration of Artificial Synapse and Nociceptor

Bio-mimetic advanced electronic systems are emergingrapidly, engrossingtheir applications in neuromorphic computing, humanoid robotics, tactilesensors, and so forth. The biological synaptic and nociceptive functionsare governed by intricate neurotransmitter dynamics that involve bothshort-term and long-term plasticity. To emulate the neuronal dynamicsin an electronic device, an Ag/TiO2/Pt/SiO2/Simemristor is fabricated, exhibiting compliance current controlledreversible transition of volatile switching (VS) and non-volatileswitching (NVS). The origin of the VS and NVS depends on the diameterof the conducting filament, which is explained using a field-inducednucleation theory and validated by temporal current response measurements.The switching delay of the device is used to determine the characteristicnociceptive behaviors such as threshold, relaxation, inadaptation,allodynia, and hyperalgesia. The short-term and long-term retentionloss attributed to the VS and NVS, respectively, is used to emulateshort-term memory and long-term memory of the biological brain ina single device. More importantly, synergistically modulating theVS-NVS transition, the complex spike rate-dependent (SRDP)and spike time-dependent plasticity (STDP) with a weight change ofup to 600% is demonstrated in the same device, which is the highestreported so far for TiO2 memristors. Furthermore, the deviceexhibits very low power consumption, similar to 3.76 pJ/spike, and canimitate synaptic and nociceptive functions. The consolidation of complexnociceptive and synaptic behavior in a single memristor facilitateslow-power integration of scalable intelligent sensors and neuromorphicdevices.