Fig. 6
From: Multi-level resistive switching in hafnium-oxide-based devices for neuromorphic computing
Illustration of threshold switching (TS) and neuronal functionality. a TS is unipolar and volatile. At a certain voltage, the current increases rapidly from the HRS to the LRS, but when the voltage is reduced, the current and the conductivity decrease back to the HRS. This could be used to implement a selector functionality to suppress sneak paths in crossbar arrays. b It could also be used to implement neuronal (as opposed to synaptic) functionality in this simple circuit for an integrate-and-fire neuron based on a TS device. Subsequent input pulses charge the ‘membrane’ capacitor Cm. When its potential reaches the threshold Vswitching of the TS element, the signal is transmitted and Cm discharges through the LRS TS element and Rdischarge. c Schematic membrane voltage Vm on Cm for an arbitrary input signal. As long as the potential on Cm remains below the switching threshold Vswitching, the TS device will remain insulating. Only when the switching threshold is surpassed, will a signal, such as a current to emulate neuronal firing, be possible