We present a thorough experimental study of the three-dimensional hyperhoneycomb Kitaev magnet $\beta \text{−}{\mathrm{Li}}_2{\mathrm{IrO}}_3$, using a combination of inelastic neutron scattering (INS), time-domain terahertz spectroscopy (TDTS), and heat capacity measurements. The main results include a massive low-temperature reorganization of the INS spectral weight that evolves into a broad peak centered around 12 meV, and a distinctive peak in the terahertz data at 2.8(1) meV. A detailed comparison to powder-averaged spin-wave theory calculations reveals that the positions of these two features are controlled by the anisotropic $\mathrm{\Gamma }$ coupling and the Heisenberg exchange $J$, respectively. The refined microscopic spin model places $\beta \text{−}{\mathrm{Li}}_2{\mathrm{IrO}}_3$ in close proximity to the Kitaev spin liquid phase.

中文翻译：

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Kitaev hyperhoneycomb iridateβ-Li2IrO3 中的磁激发和相互作用

我们对三维超蜂窝基塔耶夫磁体进行了深入的实验研究$\beta \text{-}{李}_2{\mathrm{氧化铁}}_3$，结合使用非弹性中子散射 (INS)、时域太赫兹光谱 (TDTS) 和热容量测量。主要结果包括 INS 光谱权重的大规模低温重组，演变成以 12 meV 为中心的宽峰，以及 2.8(1) meV 的太赫兹数据中的独特峰。与粉末平均自旋波理论计算的详细比较表明，这两个特征的位置由各向异性控制$\mathrm{\Gamma }$耦合和海森堡交换$Ĵ$， 分别。精细的微观自旋模型放置$\beta \text{-}{李}_2{\mathrm{氧化铁}}_3$靠近 Kitaev 自旋液相。