标题： 磁序诱导的铁磁外尔半金属中的手性声子 显示英文标题

标题： Magnetic order induced chiral phonons in a ferromagnetic Weyl semimetal

摘要： 手性声子是晶体中具有明确手性或螺旋性的振动模式，通常存在于缺乏倒置对称性的材料中。 在此，我们报告在kagome铁磁外尔半金属Co3Sn2S2中发现了手性声子模式，这是一种保持倒置对称性但破坏时间反演对称性的材料。 使用旋向分辨的磁拉曼光谱，我们观察到当样品在居里温度以下无磁场冷却时，平面内Eg双简并模式自发分裂为两种具有相反旋向的手性声子模式，在没有外部磁场的情况下。 当我们扫描面外磁场时，这种Eg声子分裂表现出与材料磁化强度直接相关的明确迟滞回路。 观察到的自发分裂在低温下可达1.27 cm-1，随着温度升高逐渐减小，并在接近居里温度时完全消失。 我们的发现突显了磁序在诱导手性声子中的作用，为通过磁化操控手性声子以及反之提供了新方法。 此外，我们的工作为利用手性声子控制手性外尔费米子提供了新的可能性。 显示英文摘要

摘要： Chiral phonons are vibrational modes in a crystal that possess a well-defined handedness or chirality, typically found in materials that lack inversion symmetry. Here we report the discovery of chiral phonon modes in the kagome ferromagnetic Weyl semimetal Co3Sn2S2, a material that preserves inversion symmetry but breaks time-reversal symmetry. Using helicity-resolved magneto-Raman spectroscopy, we observe the spontaneous splitting of the doubly degenerate in-plane Eg modes into two distinct chiral phonon modes of opposite helicity when the sample is zero-field cooled below the Curie temperature, in the absence of an external magnetic field. As we sweep the out-of-plane magnetic field, this Eg phonon splitting exhibits a well-defined hysteresis loop directly correlated with the material's magnetization. The observed spontaneous splitting reaches up to 1.27 cm-1 at low temperatures, progressively diminishes with increasing temperature, and completely vanishes near the Curie temperature. Our findings highlight the role of the magnetic order in inducing chiral phonons, paving the way for novel methods to manipulate chiral phonons through magnetization and vice versa. Additionally, our work introduces new possibilities for controlling chiral Weyl fermions using chiral phonons.