We present magnetization measurements on polycrystalline $\beta \text{−}{\mathrm{Li}}_2{\mathrm{IrO}}_3$ under hydrostatic pressures up to 3 GPa and construct the temperature-pressure phase diagram of this material. Our data confirm that magnetic order breaks down in a first-order phase transition at $p_{\mathrm{c}}\approx 1.4$ GPa and additionally reveal a steplike feature—magnetic signature of structural dimerization—that appears at $p_{\mathrm{c}}$ and shifts to higher temperatures upon further compression. Following the structural study by L. S. I. Veiga et al. [Phys. Rev. B 100, 064104 (2019)], we suggest that a partially dimerized phase with a mixture of magnetic and nonmagnetic ${\mathrm{Ir}}^{4+}$ sites develops above $p_{\mathrm{c}}$. This phase is thermodynamically stable between 1.7 and 2.7 GPa according to our ab initio calculations. It confines the magnetic ${\mathrm{Ir}}^{4+}$ sites to weakly coupled tetramers with a singlet ground state and no long-range magnetic order. Our results rule out the formation of a pressure-induced spin-liquid phase in $\beta \text{−}{\mathrm{Li}}_2{\mathrm{IrO}}_3$ and reveal peculiarities of the magnetism collapse transition in a Kitaev material. We also show that a compressive strain imposed by the pressure treatment of $\beta \text{−}{\mathrm{Li}}_2{\mathrm{IrO}}_3$ enhances signatures of the 100 K magnetic anomaly at ambient pressure.

中文翻译：

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加压的 Kitaev 材料β-Li2IrO3 中磁性和二聚化的相互作用

我们提供了多晶的磁化测量 $\beta \text{-}{李}_2{\mathrm{氧化铁}}_3$在高达 3 GPa 的静水压力下，构建该材料的温度-压力相图。我们的数据证实磁序在一级相变中分解${磷}_{\mathrm{C}}\approx 1.4$ GPa 并另外揭示了一个阶梯状特征——结构二聚化的磁性特征——出现在 ${磷}_{\mathrm{C}}$并在进一步压缩时转移到更高的温度。根据 LSI Veiga等人的结构研究。[物理。Rev. B 100 , 064104 (2019)]，我们建议使用磁性和非磁性混合物的部分二聚相${\mathrm{红外线}}^{4+}$ 网站在上面发展 ${磷}_{\mathrm{C}}$. 根据我们的ab initio计算，该相在 1.7 到 2.7 GPa 之间是热力学稳定的。它限制了磁${\mathrm{红外线}}^{4+}$位点到具有单线基态且没有长程磁序的弱耦合四聚体。我们的结果排除了压力诱导自旋液相的形成$\beta \text{-}{李}_2{\mathrm{氧化铁}}_3$并揭示了 Kitaev 材料中磁坍缩转变的特性。我们还表明，由压力处理施加的压缩应变$\beta \text{-}{李}_2{\mathrm{氧化铁}}_3$ 增强了环境压力下 100 K 磁异常的特征。