论文标题
旋转轴耦合驱动电荷密度波在kagome磁铁中
Spin-phonon coupling driven Charge density wave in a Kagome Magnet
论文作者
论文摘要
自旋，电荷和晶格自由度之间的相互交织可能会导致异常的宏观量子状态，包括高温超导性和量子异常的霍尔效应。最近，在kagome抗feRomagnet Fege中观察到电荷密度波（CDW），这表明可能相互交织的物理学。一个杰出的问题是，磁相关是否对于自发的空间对称性破坏顺序是否至关重要。在这里，利用弹性和高分辨率的非弹性X射线散射，我们发现了一个电荷二聚体超晶格，与2 $ \ times $ 2 $ \ times $ \ times $ \ times $ 1 $ 1 CDW共存。最有趣的是，在磁性和CDW过渡温度之间，声子动态结构因子显示出巨大的声子 - 能量硬化，并且在电荷 - 二级波动vectors附近宽阔的声子线宽扩大，这两者都会发出旋转量子耦合的信号。通过第一原理计算，我们表明静态和动态旋转激发与声子交织在一起以驱动空间对称性破裂。
The intertwining between spin, charge, and lattice degrees of freedom can give rise to unusual macroscopic quantum states, including high-temperature superconductivity and quantum anomalous Hall effects. Recently, a charge density wave (CDW) is observed in the kagome antiferromagnet FeGe, indicative of possible intertwining physics. An outstanding question is that whether magnetic correlation is fundamental for the spontaneous spatial symmetry breaking orders. Here, utilizing elastic and high-resolution inelastic x-ray scattering, we discover a charge dimerization superlattice that coexists with the 2$\times$2$\times$1 CDW in the kagome sublattice. Most interestingly, between the magnetic and CDW transition temperature, the phonon dynamical structure factor shows a giant phonon-energy hardening and a substantial phonon linewidth broadening near the charge-dimerization wavevectors, both signaling the spin-phonon coupling. By first principles calculations, we show that both the static and dynamic spin excitations intertwine with the phonon to drive the spatial symmetry breaking.
