Observation of the spiral spin liquid in a triangular-lattice material

• DOI: 10.1038/s41467-025-57319-2
• Publication Date: 2025-03-17T14:28:31Z
• Authors: N. D. Andriushin; S. E. Nikitin; Ø. S. Fjellvåg; J. S. White; A. Podlesnyak; D. S. Inosov; M. C. Rahn; M. Schmidt; M. Baenitz; A. S. Sukhanov

Abstract The spiral spin liquid (SSL) is a highly degenerate state characterized by a continuous contour or surface in reciprocal space spanned by a spiral propagation vector. Although the SSL state has been predicted in a number of various theoretical models, very few materials are so far experimentally identified to host such a state. Via combined single-crystal wide-angle and small-angle neutron scattering, we report observation of the SSL in the quasi-two-dimensional delafossite-like AgCrSe2. We show that it is a very close realization of the ideal Heisenberg J 1–J 2–J 3 frustrated model on the triangular lattice. By supplementing our experimental results with microscopic spin-dynamics simulations, we demonstrate how such exotic magnetic states are driven by thermal fluctuations and exchange frustration.