Modeling of VO2 Relaxation Oscillator in the Fast-Slow System Approximation

The phenomenon of the metal-insulator phase transition in polycrystalline vanadium dioxide (VO 2 ) films gave rise to a new class of nonlinear dynamical systems that have found application in neuromorphic electronics. In this article, we propose the model of VO 2 relaxation oscillator in the fast-slow systems' approximation with considering thermal processes accompanying the resistivity switching at the metal-insulator transition (MIT). The differential equations describing the oscillator were reduced to dimensionless form. By means of numerical simulations, the nonlinear system was established to exhibit four types of dynamics depending on the applied electric voltage and the small parameter value of the system. The possible phase space trajectories for the dynamical system were considered for all types of dynamics, with the bursting oscillations predicted not having been observed experimentally so far. The results of this work can be applied to the neuromorphic computer operation analysis with VO 2 -oscillator dynamics that mimics the neural activity.