The triangular-lattice quantum Ising antiferromagnet is a promising platform for realizing Anderson's quantum spin liquid, though finding suitable materials to realize it remains a challenge. Here, we present a comprehensive study of NaTmSe2 using magnetization, specific heat, neutron scattering, and muon spin relaxation, combined with theoretical calculations. We demonstrate that NaTmSe2 realizes the transverse field Ising model and quantitatively determine its exchange parameters. Our results reveal a multipolar spin-polarized state coexisting with a dipolar spin-disordered state. These states feature gapless spinon excitations mediated by the multipolar moments. The study shows how multiple types of magnetism can emerge in distinct magnetic channels (dipolar and multipolar) within a single magnet, advancing our understanding of spin-frustrated Ising physics and opening pathways for different quantum computing applications.
@article{arxiv.2505.09884,
title = {Gapless spinon excitations emerging from a multipolar transverse field in the triangular-lattice Ising antiferromagnet NaTmSe2},
author = {Zheng Zhang and Jinlong Jiao and Weizhen Zhuo and Mingtai Xie and D. T. Adroja and Toni Shiroka and Guochu Deng and Anmin Zhang and Feng Jin and Jianting Ji and Jie Ma and Qingming Zhang},
journal= {arXiv preprint arXiv:2505.09884},
year = {2025}
}