Neuromorphic Applications

Caloritronics-based aritificial neuron using a Mott insulator

“Leaky” Integrate and fire dynamics are the most basic functionality of neurons. Here we use heat pulses to generate these dynamics in a device based on the insulator-metal transition in VO2. (a) Schematics of the neuristor, showing the VO2 device biased close to the switching threshold voltage in close proximity to a nanoscale heater. (b) A large current pulse in the heater (red) heats the VO2 device up to the insulator-metal transition temperature, resulting in ”firing” – a sharp rise in current (blue). Due to the load resistor (Rload), the voltage on the VO2 device goes down after the pulse allowing it to cool down and return to the insulating phase, resulting in a pulse rather than a constantly “on” state. (c) Small heating pulses (red curve) which are unable to trigger firing individually can cause firing if the interval between them is short enough so that the VO2 temperature rises gradually with each pulse, resulting in “leaky” integrate and fire dynamics. This type of coupling between neurons obviates the need for a capacitor, which is commonly used for generating integration dynamics by charge accumulation.

See “A caloritornics based Mott-Neuristor” – del Valle J, Salev P, Kalcheim Y and IK Schuller (2020) –  Scientific Reports 10, 4929 (2020).