Embedded Three-Dimensional Bubble-Like Polar Textures with Ionic-Ordering-Assisted Stabilization in CuInP2S6.

Bubble-like polar textures in ferroelectrics offer promising opportunities for high-density memory and neuromorphic devices, yet their stabilization in intrinsic three-dimensional (3D) objects remains challenging. Here, we report embedded three-dimensional bubble-like polar textures in the van der Waals ferroionic crystal CuInP2S6 (CIPS). By combining angle-resolved vector piezoresponse force microscopy, tomographic piezoresponse force microscopy, and transmission electron microscopy, we reveal that these polar textures are isolated, capsule-shaped polar nanostructures volumetrically embedded within the CIPS lattice rather than surface-localized features. The angle-dependent piezoresponse is consistent with a center-divergent Néel-like polarization configuration, while cross-sectional microscopy indicates local site-selective Cu-ion occupancy within the embedded textures, providing a plausible structural basis for ionic-ordering-assisted stabilization. Distinct from interface-constrained polar textures in conventional oxide heterostructures, these bubble-like textures exhibit only weak size variation over a broad thickness range, suggesting an intrinsically stabilized, ionic-ordering-related origin. Furthermore, they can be reversibly reconfigured between bubble-like and quasi-single-domain states under moderate electric bias, plausibly through local Cu-ion redistribution. These findings highlight ionic ordering as a promising route for stabilizing and manipulating embedded 3D polar textures in van der Waals ferroics and suggest opportunities for electrically reconfigurable nanoscale ferroic devices.