Characterization

The steady-state insulator-metal transition of the as-prepared VO₂ thin film was confirmed by temperature-dependent resistance measurement depicted in Supplementary Fig. S2(a), showing 2 orders of magnitude change in resistance across the transition temperature T_C ~ 340 K⁶. A dispersion of ~8 K is also identified, which we attributed to the inhomogeneity-induced broadening, rather than the intrinsic property of VO₂, as evidenced in recent studies of single-crystal nanobeams^27,38,59. Also shown is the structure phase transition (see Supplementary Fig. S2(b)), monitored through the electron diffraction, in which the (3, 0, −2) intensity is used as an order parameter to gauge the degree of phase transition. We note that the measured resistivity continues to change beyond the structural transition region. This trend is indicative of a continuous change in the electronic property of VO₂ beyond T_C, not correlated with the structural phase transition^38,59.