论文标题
时间逆转对称性破坏电荷密度的CSV $ _3 $ SB $ _5 $由Polar Kerr效应检测到
Time-reversal symmetry breaking in charge density wave of CsV$_3$Sb$_5$ detected by polar Kerr effect
论文作者
论文摘要
由于其独特的几何特性，Kagome晶格表现出丰富的量子现象。有吸引力的实现是Kagome金属AV $ _3 $ SB $ _5 $（A = K，RB，CS），在该k，rb，cs）中，非常规的电荷密度波（CDW）与超导性和非平凡的乐队拓扑交织在一起。几个实验表明，这种CDW是罕见的手性CDW，其特征是轨道环电流。但是，环电流，自发的时间反转对称性（TRSB）以及其阶参数与磁场的耦合仍然难以捉摸。在这里，我们通过磁光极性Kerr效应和亚微分辨率研究了CSV3SB5中的CDW。在磁场下，我们观察到CDW过渡时Kerr角的跳跃。这种跳跃是磁场可切换的，并用场缩放，表明与非平凡带拓扑相关的磁性耦合。在零场，我们发现CDW过渡温度以下的非零和磁场可训练的KERR角，信号自发TRSB。我们的结果为揭示相关的kagome材料中的量子现象提供了至关重要的步骤。
The Kagome lattice exhibits rich quantum phenomena owing to its unique geometric properties. Appealing realizations are the Kagome metals AV$_3$Sb$_5$ (A = K, Rb, Cs), where unconventional charge density wave (CDW) is intertwined with superconductivity and non-trivial band topology. Several experiments suggest that this CDW is a rare occurrence of chiral CDW characterized by orbital loop current. However, key evidences of loop current, spontaneous time-reversal symmetry-breaking (TRSB) and the coupling of its order parameter with the magnetic field remain elusive. Here, we investigate the CDW in CsV3Sb5 by magneto-optic polar Kerr effect with sub-microradian resolution. Under magnetic field, we observed a jump of the Kerr angle at the CDW transition. This jump is magnetic-field switchable and scales with field, indicating magneto--chirality coupling related to non-trivial band topology. At zero field, we found non-zero and field-trainable Kerr angle below CDW transition temperature, signaling spontaneous TRSB. Our results provide a crucial step to unveil quantum phenomena in correlated Kagome materials.
