Current oscillations in Vanadium Dioxide: evidence for electrically triggered percolation avalanches

TL;DR

This study investigates voltage-controlled oscillations in vanadium dioxide micro-beams, proposing a modified percolative-avalanche model that emphasizes electric field effects over thermal heating as the primary trigger for phase transition-induced oscillations.

Contribution

It introduces a new voltage-triggered percolative-avalanche model for VO2 oscillations, highlighting electric field as the main driver over temperature effects.

Findings

Oscillations are voltage-controlled and related to VO2 phase transition.

The modified model accurately captures oscillation features.

Electric field, not heating, triggers the phase transition.

Abstract

In this work, we experimentally and theoretically explore voltage controlled oscillations occurring in micro-beams of vanadium dioxide. These oscillations are a result of the reversible insulator to metal phase transition in vanadium dioxide. Examining the structure of the observed oscillations in detail, we propose a modified percolative-avalanche model which allows for voltage-triggering. This model captures the periodicity and waveshape of the oscillations as well as several other key features. Importantly, our modeling shows that while temperature plays a critical role in the vanadium dioxide phase transition, electrically induced heating cannot act as the primary instigator of the oscillations in this configuration. This realization leads us to identify electric field as the most likely candidate for driving the phase transition.