Metastable 1T-RhO 2 with a Triangular Lattice: A Possible Quantum Spin Liquid Candidate

作者：Yang‐Yang Lv, Defa Liu, Haomin Lu, Yong Zhang, Zequn Sun, Sutao Sun, Lin Cao, Wensheng Yan, Wenhua Zhang, Zhenlin Luo, Zhenxiang Cheng, You Song, Shu‐Hua Yao, Jian Zhou, Yanbin Chen, Yan-Bin Chen, Yan-Feng Chen, Yan-Feng Chen · 发表于：The Journal of Physical Chemistry Letters · 年份：2025 · DOI：10.1021/acs.jpclett.5c02189 · 被引用次数：1 · 研究领域：Advanced Condensed Matter Physics、Multiferroics and related materials、Physics of Superconductivity and Magnetism

The discovery of intrinsic magnetism in layered van der Waals (vdW) magnets has received intensive attention due to their fundamental importance in low-dimensional magnetism and potential device applications. To date, most vdW magnets contain 3d transition metals. Extending vdW magnetism to 4d and 5d transition metal systems is therefore of great interest as it offers opportunities to explore exotic magnetic behaviors arising from the interplay between electronic correlations and strong spin–orbit coupling (SOC). Here, we report the successful synthesis of a metastable layered vdW triangular lattice crystal, 1T-RhO 2, through the topochemical reaction from Cs 0.5 RhO 2 single crystals. Electrical transport measurements reveal that 1T-RhO 2 is an insulator, while magnetic susceptibility and alternating current susceptibility confirm the absence of long-range magnetic order or spin glass behavior down to 2 K. Raman spectroscopy indicates fermionic excitations consistent with fractionalized Majorana fermions. Angle-resolved photoemission spectroscopy, supported by hybrid functional calculations, reveals a band gap of about 1.0 eV, further confirming the insulating nature. These results collectively suggest that 1T-RhO 2 is a possible quantum spin liquid (QSL) candidate. Our work not only sheds light on the research fields of 4d and 5d transition metal vdW magnets but also significantly expands the pathways for discovering QSL candidates in metastable materials.