Observation of Optically Addressable Nonvolatile Memory in VO2 at Room Temperature

Abstract

Vanadium dioxide (VO2) is a phase change material that can reversibly change between high and low resistivity states through electronic and structural phase transitions. Thus far, VO2 memory devices have essentially been volatile at room temperature, and nonvolatile memory has required non-ambient surroundings (e.g., elevated temperatures, electrolytes) and long write times. For the first time, here, the authors report the observation of optically addressable nonvolatile memory in VO2 at room temperature with a readout by voltage oscillations. The read and write times have to be kept shorter than about 150 µs. The writing of the memory and onset of the voltage oscillations have a minimum optical power threshold. Although the physical mechanisms underlying this memory effect require further investigations, this discovery illustrates the potential of VO2 for new computing devices and architectures, such as artificial neurons and oscillatory neural networks.