Our latest work is published in J. Phys. Chem. C. We demonstrated metastability in the insulator–metal transition for individual vanadium dioxide nanoparticles using our mid-infrared SNOM.
Using temperature-dependent mid-infrared nanoimaging, we were able to discern the phase transition of these individual vanadium dioxide nanoparticles. Particles of smaller volumes generally transition to metal at elevated temperatures. This is attributed to fewer nucleation sites within each particle. Using mid-infrared nanoimaging, we observed that the phase transition displays a stochastic behavior: the same particle shows varying transition temperatures across different heating cycles. Our findings suggest that the phase transition in vanadium dioxide nanoparticles is prone to superheating and supercooling, and these transitions are limited by nucleation.