Universal phase dynamics in VO2 switches revealed by ultrafast operando diffraction

Understanding the pathways and time scales underlying electrically driven insulator-metal transitions is crucial for uncovering the fundamental limits of device operation. Using stroboscopic electron diffraction, we perform synchronized time-resolved measurements of atomic motions and electronic transport in operating vanadium dioxide (VO2) switches. We discover an electrically triggered, isostructural state that forms transiently on microsecond time scales, which is shown by phase-field simulations to be stabilized by local heterogeneities and interfacial interactions between the equilibrium phases. This metastable phase is similar to that formed under photoexcitation within picoseconds, suggesting a universal transformation pathway. Our results establish electrical excitation as a route for uncovering nonequilibrium and metastable phases in correlated materials, opening avenues for engineering dynamical behavior in nanoelectronics.

Automated summary

Understanding the pathways and time scales underlying electrically driven insulator-metal transitions is vital for uncovering the fundamental limits of device operation. By using stroboscopic electron diffraction, researchers discovered an electrically triggered, isostructural state that forms transiently on microsecond time scales and established electrical excitation as a route for uncovering nonequilibrium and metastable phases in correlated materials. This metastable phase is similar to that formed under photoexcitation within picoseconds, suggesting a universal transformation pathway.