论文标题
损坏引起的本地电动极化为$α$ -rucl $ _3 $的证据
Evidence for distortion-induced local electric polarization in $α$-RuCl$_3$
论文作者
论文摘要
旋转轨道辅助Mott绝缘子$α$ -RUCL $ _3 $是材料实现Kitaev量子旋转液体的主要候选者。尽管对充电程度的自由度几乎没有关注，但在该系统中可能会出现电荷效应，例如电动极化。在这里，我们报告了单晶X射线衍射，第二次谐波（SHG）和介电测量结果证明了失真引起的局部电化$ -rucl $ _3 $中的局部电化。 SHG信号出现在室温下，当短距离自旋相关性发挥作用时，在Kitaev Promagnetic状态下会大大发展。尽管在基塔夫拉磁磁状态下具有相当大的pyroelectric电流，但电场依赖性极化（P-e）中缺乏滞后表明电动极化的短距离性质。这种局部的电化极化可能是通过虚拟跳跃诱导的电荷重新分布实现失真引起的电荷二聚化的结果。此外，通过在基塔夫拉磁磁态中的自旋 - 音波耦合通过短距离自旋相关性来增强电化极化。我们的结果强调了$α$ -rucl $ _3 $中自由度的重要性，该$ _3 $建立了一个新颖的平台，以在Kitaev材料中投资收费效应。
The spin-orbit assisted Mott insulator $α$-RuCl$_3$ is a prime candidate for material realization of the Kitaev quantum spin liquid. While little attention has been paid to charge degrees of freedom, charge effects, such as electric polarization, may arise in this system. Here, we report distortion-induced local electric polarization in $α$-RuCl$_3$ as evidenced by single-crystal X-ray diffraction, second harmonic generation (SHG) and dielectric measurements. The SHG signal appears at room temperature and develops substantially in the Kitaev paramagnetic state when short-range spin correlations come into play. Despite sizable pyroelectric currents in the Kitaev paramagnetic state, the absence of hysteresis in electric field-dependent polariza-tion (P-E) points to the short-range nature of electric polarization. This localized electric polarization is likely the result of distortion-induced charge dimerization, achieved through virtual hopping-induced charge redistribution. In addition, the electric polarization is boosted by short-range spin correlations via spin-phonon coupling in the Kitaev paramagnetic state. Our results emphasize the importance of charge degrees of freedom in $α$-RuCl$_3$, which establish a novel platform to investi-gate charge effects in Kitaev materials.
