Coexistence of static and dynamic magnetism in the Kitaev spin liquid material Cu2IrO3
Coexistence of static and dynamic magnetism in the Kitaev spin liquid material Cu2IrO3
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DOI：
10.1103/physrevb.100.094418
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发表时间：
2019-09-12
影响因子：
3.7
通讯作者：
Tafti, Fazel
中科院分区：
文献类型：
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作者：
Kenney, Eric M.;Segre, Carlo U.;Tafti, Fazel
对Kitaev自旋液相的研究激发了蜂窝虹酸盐材料的研究热潮。然而，磁性有序阻碍了对自旋液体基态的访问。Cu2IrO_3是一种新型的蜂窝状结构，没有长程有序的热力学特征。在这里，我们使用Muon自旋弛豫来揭示Cu2IrO_3的磁性基态。我们发现了两组分退极化，慢弛豫率和快弛豫率对应于不同的区域，动磁和静磁共存于材料中。X射线吸收光谱和第一性原理计算确定混合铜价是这一行为的根源。我们的结果表明，少量的Cu2+离子成核静磁性区域，而蜂窝晶格上的大部分Cu2+/Ir4+离子形成Kitaev自旋液体。
Searching for a Kitaev spin liquid phase motivated intense research on the honeycomb iridate materials. However, access to a spin liquid ground state has been hindered by magnetic ordering. Cu2IrO3 is a new honeycomb iridate without thermodynamic signatures of a long-range order. Here, we use muon spin relaxation to uncover the magnetic ground state of Cu2IrO3. We find a two-component depolarization with slow- and fast-relaxation rates corresponding to distinct regions with dynamic and static magnetism coexisting in the material. X-ray absorption spectroscopy and first-principles calculations identify a mixed copper valence as the origin of this behavior. Our results suggest that a minority of Cu2+ ions nucleate regions of static magnetism, whereas the majority of Cu+/Ir4+ on the honeycomb lattice give rise to a Kitaev spin liquid.