We present several approximate calculations of the specific heat capacity of the model for ${\mathrm{Ca}}_{10}{\mathrm{Cr}}_7{\mathrm{O}}_{28}$ proposed by Balz et al. [Phys. Rev. B 95, 174414 (2017)], using methods including exact diagonalization, thermal pure quantum states, and high-temperature expansions. In none of these cases are we able to reproduce the magnitude of the zero-field specific heat capacity shown in the intermediate-temperature $(\sim 5–15\mathrm{K})$ experimental data. We discuss possible reasons for the discrepancy, and what it might tell us about the magnetic Hamiltonian for ${\mathrm{Ca}}_{10}{\mathrm{Cr}}_7{\mathrm{O}}_{28}$.

中文翻译：

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自旋液体候选物Ca10Cr7O28中温磁比热容的起源

我们提出了模型比热容的几种近似计算${钙}_{10}{铬}_7{\mathrm{氧}}_{28}$Balz等人提出。 [物理。 Rev. B 95 , 174414 (2017)]，使用的方法包括精确对角化、热纯量子态和高温膨胀。在这些情况下，我们都无法重现中间温度中显示的零场比热容的大小$（～5–15\mathrm{K}）$实验数据。我们讨论了这种差异的可能原因，以及它可能告诉我们关于磁哈密顿量的什么信息${钙}_{10}{铬}_7{\mathrm{氧}}_{28}$。