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arXiv 2208.08036cond-mat.str-el
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极性克尔效应探测CsV $_3$ Sb $_5$电荷密度波的时间反演对称性破缺

Time-reversal symmetry breaking in charge density wave of CsV$_3$Sb$_5$ detected by polar Kerr effect

Yajian Hu, Soichiro Yamane, Giordano Mattoni, Kanae Yada, Keito Obata, Yongkai Li, Yugui Yao, Zhiwei Wang, Jingyuan Wang, Camron Farhang, Jing Xia, Yoshiteru Maeno, Shingo Yonezawa

摘要:

由于其独特的几何性质,Kagome晶格表现出丰富的量子现象。吸引人的实现是可果美金属AV $_3$ Sb $_5$(A = K,Rb,Cs),其中非常规电荷密度波(CDW)与超导性和非平凡能带拓扑交织在一起。几个实验表明,这CDW是一个罕见的发生手性CDW的特点是轨道环电流。然而,环电流,自发时间反转破缺(TRSB)及其序参量与磁场耦合的关键证据仍然难以捉摸。本文利用磁光极向克尔效应研究了CsV_3Sb_5中的CDW。在磁场作用下,我们观察到了CDW跃迁处的克尔角突变。这种跳跃是磁场可切换的,并与字段的规模,表示磁--手性耦合相关的非平凡带拓扑结构。在零场时,我们发现非零和场可训练的克尔角低于CDW转变温度,信号自发TRSB。我们的研究结果为揭示相关Kagome材料中的量子现象提供了关键的一步。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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