Year: 2026
Type: preprint
Abstract: Understanding the principles governing the emergence of chiral quantum phases is a fundamental challenge, not only for uncovering new mechanisms of quantum-state formation but also for realizing giant electronic responses and transport phenomena arising from chirality and topology. While Fermi-surface instabilities in metals can stabilize complex ordered states through multiple competing scattering channels, their microscopic origin is often obscured by the complexity of the underlying electronic structure, limiting the development of general microscopic design principles. Here, we introduce a complementary strategy based on the simplicity of semiconductor band extrema. Using the layered van der Waals semiconductor GdGaI, whose low-energy electronic structure consists of simple electron and hole valleys, we discover the spontaneous emergence of an intertwined chiral triple-$q$ antiferromagnetic state accompanied by a cooperative reconstruction of the electron-hole band edges, beyond the conventional expectation of a single-$q$ ground state. This collective reconstruction generates substantial momentum-space Berry curvature, giving rise to a pronounced spontaneous anomalous Hall effect despite the semiconducting character and negligible net magnetization. Remarkably, this chiral state is realized within an atomically well-defined ($\approx2a$), topologically nontrivial magnetic texture, showing that such collective quantum states can emerge at an exceptionally small length scale from a simple two-dimensional magnetic semiconductor. More broadly, our results introduce a remarkably simple design concept for chiral quantum matter: using simple semiconductor band extrema as building blocks for resonance-like interplay in momentum space, providing a route to Berry curvature, topological transport, and emergent quantum phases.
Source: arXiv (Cornell University)
Authors: Okuma, R., Ikenobe, T., Fujisawa, Y., Yamagami, K., Wu, H. C. H., Nakamura, T., Ihara, Y., Ishikawa, H., Suwa, H., Ishizuka, H., Akagi, Y., Kaneko, T., Hsu, C. H., Obata, Y., Tomoda, N., Dronova, M., Nagasawa, K., Saito, H., Ueta, D., Sagayama, H., Yamaura, J., Arita, M., Yogendra, K., Ideta, S., Kindo, K., Nakajima, T., Blundell, S. J., Kondo, T., Shimada, K., Okamoto, Y., Okada, Y.
Institutions: Okinawa Institute of Science and Technology Graduate University, The Institute for Solid State Physics, The University of Tokyo, Hiroshima University, Research Institute for Synchrotron Radiation Science, Hiroshima University, Japan Synchrotron Radiation Research Institute, University of Oxford, Hokkaido University, Tokyo University of Science, The University of Tokyo, Institute of Science Tokyo, Ochanomizu University, The University of Osaka, High Energy Accelerator Research Organization, Institute of Materials Structure Science
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: Dynamics of topological phases emerging from electron correlation, G2717820656, G3300572305, Real and reciprocal spacetime imaging of many-body excitons and quantum phase control, Realization of bond-directional magnetism in three-dimensional honeycomb lattices, アニオン遷移金属種が示す電子物性の開拓, Correlated electronic states and photoinduced phenomena in bilayer systems, G5322376047, Topological magnetism realized by excitonic instability, G5947901663, 磁気多極子を軸としたトポロジカル磁性の統一的理論展開, G6842830595, G7548693940, G7803507214
OpenAlex ID: W7213291784