Coexisting phases of individual VO$_2$ nanoparticles for multilevel nanoscale memory

TL;DR

This study investigates the phase transition behavior of individual VO$_2$ nanoparticles in real time, revealing their potential for multilevel nanoscale memory applications due to stable coexisting phases near room temperature.

Contribution

It provides the first real-time analysis of hysteresis dynamics in single VO$_2$ nanoparticles, highlighting their phase stability and memory capabilities at near-room temperatures.

Findings

Statistical distribution of transition temperatures and steepness during heating and cooling.

Persistent multilevel memory demonstrated with a few VO$_2$ nanoparticles.

Insights into physical mechanisms of hysteresis in VO$_2$ nanoparticles.

Abstract

Vanadium dioxide (VO$_2$) has received significant interest in the context of nanophotonic metamaterials and memories owing to its reversible insulator-metal transition associated with significant changes in its optical and electronic properties. While the VO$_2$ transition has been extensively studied for several decades, the hysteresis dynamics of individual single-crystal VO$_2$ nanoparticles (NPs) remains largely unexplored. Here, employing transmission electron microscopy techniques, we investigate phase transitions of single VO$_2$ NPs in real time. Our analysis reveals the statistical distribution of the transition temperature and steepness and how they differ during forward (heating) and backward (cooling) transitions. We assess the stability of coexisting phases in individual NPs and prove the persistent multilevel memory at near-room temperatures using only a few VO$_2$ NPs. Our findings shed new light on the underlying physical mechanisms governing the hysteresis of VO$_2$ and establish VO$_2$ NPs as a promising component of optoelectronic and memory devices with enhanced functionalities.