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Description
V2O3 is a prototypical Mott insulator in which the first-order insulator-to-metal transition (IMT) is accompanied by a symmetry-breaking lattice distortion. In the low-temperature insulating-antiferromagnetic-monoclinic phase, the breaking of three-fold rotational symmetry generates an intrinsic nanotexture composed of differently oriented domains [1]. This nanoscale texture plays a central role in determining the nucleation and propagation of the metallic phase; here, we investigate its role when the IMT is triggered by a static electric field in a resistive switching geometry.
The nanotexture is imaged by PhotoEmission Electron Microscopy (PEEM), exploiting X-ray Linear Dichroism (XLD) at the V L2,3 edge (∼513–530 eV) as a contrast mechanism sensitive to domain orientation. By combining PEEM imaging with the application of voltage across micro-patterned electrodes, we directly visualize the spatial pathway of the electrically driven transition. During resistive switching, the formation of metallic filaments is not random but nucleates at topological defects emerging from the C₃-symmetry–broken insulating nanotexture [2], demonstrating that the pre-existing domain pattern governs the switching process. In addition, we reveal a striking non-volatile effect of the electric field on the insulating nanotexture. When applied to a pristine device, the field induces a macroscopic reorientation of monoclinic domains persisting after removal of the current, driving the system into a global energy minimum that cannot be accessed by thermal cycling alone. These findings provide direct real-space insight into switching mechanisms in Mott insulators, highlighting the key role of the intrinsic nanotexture and its manipulation for controlling Mott resistive switching, and establishing memory effects relevant for neuromorphic functionalities.