Systematic variation of the low-temperature heat transport properties of the quasi-two-dimensional quantum spin liquid (QSL) candidate ${\beta }^{\prime }\text{−}{\mathrm{EtMe}}_3\mathrm{Sb}\left[\mathrm{Pd}\right({\mathrm{dmit})}_2{]}_2$ and its analog compounds showing antiferromagnetic (AFM) ordering is discussed using thermal conductivity $\kappa$ measurements. All compounds with the QSL ground state show a monotonic decrease in $\kappa$ with decreasing temperature, which is a typical feature of glass or amorphous materials, caused by their low-energy phonon structures. In contrast, the AFM compounds exhibit a peak structure of $\kappa$ around 10 K, which is the characteristic temperature dependence of normal crystals with coherent phonons. Our results indicate that the anomalous glassy behavior in ${\beta }^{\prime }\text{−}{\mathrm{EtMe}}_3\mathrm{Sb}\left[\mathrm{Pd}\right({\mathrm{dmit})}_2{]}_2$ is an intrinsic and universal feature of the organic QSL phase and is not caused by extrinsic factors, such as the quality of the samples and the microcracks occurring during the cooling process. We propose a scenario for the origin of the glassy behavior of QSL compounds in which the charge fluctuation within the Pd(${\mathrm{dmit})}_2$ dimers changes the phonon properties from crystalline to glasslike.

中文翻译：

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有机三角晶格系统热导率的系统研究β′-X[Pd(dmit)2]2

准二维量子自旋液体（QSL）候选物低温热传输特性的系统变化${\beta }^{\text{'}}\text{-}{\mathrm{乙胺}}_3锑\left[钯\right({\mathrm{承认})}_2{]}_2$及其显示反铁磁 (AFM) 排序的类似化合物使用热导率进行了讨论$\kappa$测量。所有具有 QSL 基态的化合物在$\kappa$随着温度的降低，这是玻璃或无定形材料的典型特征，这是由它们的低能声子结构引起的。相比之下，AFM 化合物的峰结构为$\kappa$大约 10 K，这是具有相干声子的普通晶体的特征温度依赖性。我们的结果表明，在${\beta }^{\text{'}}\text{-}{\mathrm{乙胺}}_3锑\left[钯\right({\mathrm{承认})}_2{]}_2$是有机 QSL 相的内在和普遍特征，不是由外在因素引起的，例如样品的质量和冷却过程中发生的微裂纹。我们提出了一个关于 QSL 化合物玻璃态行为起源的场景，其中 Pd 内的电荷波动（${\mathrm{承认})}_2$二聚体将声子特性从结晶变为玻璃状。