Stochastic firing with exponential escape rate in Mott neurons

17.03.2022 15:30 – 17:30

Application of a strong electric field to a Mott material like vanadium dioxide results in an insulator-to-metal transition (IMT) characterized by a sharp drop of the resistance and the formation of metallic filaments longitudinal to the electric field [1]. The ensuing surge of the current that flows through the sample can be exploited to implement a spiking behaviour akin to that of biological neurons. However, close to the electric field threshold the delay time for the filament formation becomes increasingly unpredictable, and a proper physical understanding of the phenomenon was still missing. In this presentation we describe our recent work on this problem. By means of numerical simulations based on the Mott Resistor Network (MRN) model we show that the filament formation is inherently stochastic and analogous to an activated behavior [2]. More precisely, we show that it is a Poisson point process with a probability distribution identical to the exponential escape rate of the firing probability of realistic biological neuronal models. We validate our theoretical model findings with experimental measurements of resistive switching in VO2. Our work clarifies the physics of the filamentary incubation in Mott materials and unveils a new remarkable neuromorphic property of VO2 Mott neurons, namely the exponential escape rate spiking.
[1] del Valle et al. Science 2022
[2] R. Rocco et al. Phys Rev App 2022

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Bâtiment: Ecole de Physique

Auditoire Stückelberg,

entrée libre