Dynamics of voltage-driven oscillating insulator-metal transitions
Yin Shi, Amy Duwel, Dennis M. Callahan, Yifei Sun, F. Anika Hong, Haricharan Padmanabhan, Venkatraman Gopalan, Roman Engel‐Herbert, Shriram Ramanathan, Long‐Qing Chen
Abstract
Recent experiments demonstrated emerging alternating insulator and metal phases in Mott insulators actuated by a direct bias voltage, leading to oscillating voltage outputs with characteristic frequencies. Here, we develop a physics-based nonequilibrium model to describe the dynamics of oscillating insulator-metal phase transitions and experimentally validate it using a ${\text{VO}}_{\text{2}}$ device as a prototype. The oscillation frequency is shown to scale monotonically with the bias voltage and series resistance and terminate abruptly at lower and upper device-dependent limits, which are dictated by the nonequilibrium carrier dynamics. We derive an approximate analytical expression for the dependence of the frequency on the device operating parameters, which yields a fundamental limit to the frequency and may be utilized to provide guidance to potential applications of insulator-metal transition materials as building blocks of brain-inspired non-von Neumann computers.