Superelastic Metal-Insulator Phase Transition In Single-Crystal Vo2 Nanobeams

We investigated external-stress-induced metal-insulator phase transitions in cantilevered single-crystal VO2 nanobeams at variable temperatures using a combined theoretical and experimental approach. An atomic force microscope was used to measure the force-displacement curve of the nanobeams, which showed nonlinearity that signifies activation and expansion of domains of a new phase out of the old one. Superelasticity of the VO2 nanobeam and supersaturation of the phase transition were clearly observed and quantified within the general theory of first-order phase transitions. Phase field modeling was employed to understand the energetics of the domain formation.