  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.
