Magnetic excitations of the Kitaev model candidate RuBr3

IF 6.6 1区物理与天体物理 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

npj Quantum Materials Pub Date : 2026-03-11 DOI:10.1038/s41535-026-00868-6

Kazuhiro Nawa, Yoshinori Imai, Maiko Kofu, Richard Mole, Hideyuki Fujihara, Takumi Hiraoka, Ryo Murasaki, Pharit Piyawongwatthana, Daisuke Okuyama, Hirotada Gotou, Kenya Ohgushi, Taku J. Sato

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Abstract

The Kitaev model, which consists of bond-dependent Ising interactions on the honeycomb plane, is known as a promising model for realising a spin liquid in the exact ground state. Since bond-dependent Ising interactions are induced by orbital exchange processes via ligand ions, it is important to reveal the effect of ligand ions on the formation of bond-dependent Ising interactions experimentally. In this study, we performed powder inelastic neutron scattering on RuBr3 with a layered honeycomb structure, which is isostructural to the low-temperature structure of α-RuCl3. Strongly dispersive magnetic modes were observed near the centre of the antiferromagnetic zone below TN. With increasing temperature, the spectral weight remains near the centre of the antiferromagnetic zone just above TN, whereas it shifts to the Γ point at 3TN. Strong dispersion indicates that antiferromagnetic interactions that stabilise the zigzag antiferromagnetic order, namely, nearest-neighbour symmetric off-diagonal or third-neighbour isotropic magnetic interactions, are comparable to or even stronger than ferromagnetic Kitaev interactions, and drive the ground state of RuBr3 away from the ideal ferromagnetic Kitaev spin liquid state.

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Kitaev模型候选者RuBr3的磁激励

基塔耶夫模型由蜂窝平面上依赖键的伊辛相互作用组成，被认为是实现精确基态自旋液体的有前途的模型。由于依赖键的伊辛相互作用是由配体离子的轨道交换过程诱导的，因此通过实验揭示配体离子对形成依赖键的伊辛相互作用的影响是很重要的。在本研究中，我们对具有层状蜂窝结构的RuBr3进行了粉末非弹性中子散射，该结构与α-RuCl3的低温结构相同。在TN以下的反铁磁区中心附近观察到强色散磁模式，随着温度的升高，谱权保持在TN以上的反铁磁区中心附近，而在3TN时则向Γ点移动。强色散表明，稳定之形反铁磁秩序的反铁磁相互作用，即最近邻对称非对角线或第三近邻各向同性磁相互作用，与铁磁基塔耶夫相互作用相当甚至更强，并使RuBr3的基态远离理想的铁磁基塔耶夫自旋液态。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

npj Quantum Materials Materials Science-Electronic, Optical and Magnetic Materials

CiteScore

10.60

自引率

3.50%

发文量

107

审稿时长

6 weeks

期刊介绍： npj Quantum Materials is an open access journal that publishes works that significantly advance the understanding of quantum materials, including their fundamental properties, fabrication and applications.