- Open Access
Intertwined Polar, Chiral, and Ferro-Rotational Orders in a Homo-Ferro-Rotational Insulator
Phys. Rev. X 16, 021030 – Published 8 May, 2026
DOI: https://doi.org/10.1103/wkgv-lsj6
Abstract
Intertwined orders refer to strongly coupled and mutually dependent orders that coexist in correlated electron systems, often underpinning key physical properties of the host materials. Among them, polar, chiral, and ferro-rotational orders have been theoretically known to form a closed set of intertwined orders. However, experimental investigation into their mutual coupling and physical consequences has remained elusive. In this work, we employ the polar-chiral insulator as a platform and utilize a multimodal optical approach to directly probe and reveal the intertwining among polarity, chirality, and ferro-rotational order. We demonstrate how their coupling governs the formation of domains and dictates the nature of domain walls. Within the domains, we identify spatial inversion symmetry as the operation connecting two domain states of opposite polarity and chirality, with a homo-ferro-rotational state serving as the prerequisite for these interlocked configurations. At the domain walls, we observe a pronounced enhancement of in-plane polarization accompanied by a suppression of chirality. By combining with Ginzburg-Landau theory within the framework of a preexisting homo-ferro-rotational background, we uncover the emergence of mixed Néel- and Bloch-type domain walls. Our findings highlight the critical role of intertwined orders in defining domain and domain-wall characteristics and open pathways for domain switching and domain-wall control via intertwined order parameters.
Physics Subject Headings (PhySH)
Popular Summary
Understanding how intertwined orders influence the formation of domain walls is a significant challenge in strongly correlated systems, as the mutual coupling between states of distinct symmetries remains largely unexplored experimentally. We approached this by investigating , a prototypical material hosting intricately coupled polar, chiral, and ferro-rotational orders. Using multimodal optical characterizations combined with Ginzburg-Landau theory, we demonstrated that spatial inversion connects the two polar-chiral domain states and identified a uniform ferro-rotational state as the key coupling mechanism between polar and chiral orders. Our measurements further revealed that the domain walls separating these domain states exhibit mixed Bloch- and Néel-type character. Together, these findings highlight the role of intertwined orders in shaping the internal structure of domain boundaries. Our work establishes a foundation for engineering and controlling domain-wall behaviors through the manipulation of multiple intertwined order parameters in complex materials.
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