X-ray Nanoimaging of a Heterogeneous Structural Phase Transition in V2O3

Abstract

Controlling the Mott transition through strain engineering is crucial for advancing the development of memristive and neuromorphic computing devices. Yet, Mott insulators are heterogeneous due to intrinsic phase boundaries and extrinsic defects, posing significant challenges to fully understanding the impact of microscopic distortions on the local Mott transition. Here, using a synchrotron-based scanning X-ray nanoprobe, we studied the real-space structural heterogeneity during the structural phase transition in a V₂O₃ thin film. Through temperature-dependent metal–insulator phase coexistence mapping, we report a variation in the local transition temperature up to 7 K across the film and nanoscale transition hysteresis. Furthermore, we reveal that the spatial heterogeneity of the transition is closely tied to the tilting of crystallographic planes. Our work highlights the impact of local heterogeneity on the Mott transition and lays the groundwork for future innovations in harnessing strain heterogeneity within Mott systems for the next-generation computational technologies.