In frustrated Ising magnets, classical spin liquids (CSLs) with macroscopic ground-state degeneracy can survive against conventional magnetic order, as exemplified by systems on triangular, kagome and pyrochlore lattices at zero field. Here we report the discovery of a high-field route toward spin liquids in a bilayer triangular lattice antiferromagnet, Rb2Co2(SeO3)3. We demonstrate that a cascade of CSLs -- characterized by doubly degenerate one-up-one-down local spin configurations and a residual entropy of 1/2(1-M/M_s)Rln2 per mole -- emerges through field-controlled dilution of Ising dimers. Owing to the interplay of intra- and inter-layer interactions, these CSLs are further stabilized by lattice symmetry breaking at fractional magnetization plateaus. Such field-induced spin liquids can be understood as a consequence of generalized ice rules, analogous to those governing in pyrochlore antiferromagnets. In particular, the 5/6-plateau state is a candidate quantum spin liquid. Our results thereby establish a new pathway for exploring diverse spin liquid states across both classical and quantum regimes.
@article{arxiv.2604.03737,
title = {Cascade of Spin Liquids in a Bilayer Triangular-lattice Antiferromagnet Rb_2Co_2(SeO_3)_3},
author = {Xiaoyu Xu and Yunlong Wang and Xuejuan Gui and Jun Luo and Guijing Duan and Ke Shi and Zhaosheng Wang and Shuo Li and Huifen Ren and Chuanying Xi and Langsheng Ling and Zhanlong Wu and Ying Chen and Xiaohui Bo and Xinyu Shi and Kefan Du and Rui Bian and Jie Yang and Yi Cui and Rui Zhou and Jinchen Wang and Rong Yu and Weiqiang Yu},
journal= {arXiv preprint arXiv:2604.03737},
year = {2026}
}