Competition in the Dark: Revealing Mesoscale Competition in quantum systems using Dark-Field X-ray Microscopy

Synchrotron-based imaging modalities provide the potential for studying deeply embedded structures non-destructively. Recently, dark-field x-ray microscopy (DFXM) has provided unprecedented full-field, structural imaging of quantum materials at low temperatures and under voltage applications. This talk will provide an overview of recent measurements on neuromorphic devices, specifically VO₂-based devices, under operation. With the ability to image devices under operation, a new medium-term memory was revealed mediated by local pinned domains which act as nucleation sites. Additionally, the filament structure of these device is shown to be heterogeneous with interspersed monoclinic insulating phases within the rutile metallic filament. The insight from DFXM provides a glimpse into the competition of phases within this system during operation. This study exemplifies how mesoscale structural competition can dictate macroscopic behaviors often seen in quantum systems. With next-generation light sources coming online, the potential to perform measurements of irreversible processes, magnetic order and other quantum phenomena at the nano- and mesoscale can be enhanced using improvements to coherent flux density. This talk will conclude with a brief discussion of the future of this technique and the opportunities these new developments present for the studies of quantum systems such as charge density waves and spiral magnetic orderings.