Graham J N, Mielke Iii C, Das D, Morresi T, Sazgari V, Suter A, Prokscha T, Deng H, Khasanov R, Wilson S D, Salinas A C, Martins M M, Zhong Y, Okazaki K, Wang Z, Hasan M Z, Fischer M H, Neupert T, Yin J -X, Sanna S, Luetkens H, Salman Z, Bonfà P, Guguchia Z
Laboratory for Muon Spin Spectroscopy, PSI Center for Neutron and Muon Sciences, Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*), Fondazione Bruno Kessler, Trento, Italy.
Nat Commun. 2024 Oct 17;15(1):8978. doi: 10.1038/s41467-024-52688-6.
The breaking of time-reversal symmetry (TRS) in the normal state of kagome superconductors AVSb stands out as a significant feature, but its tunability is unexplored. Using low-energy muon spin rotation and local field numerical analysis, we study TRS breaking as a function of depth in single crystals of RbVSb (with charge order) and Cs(VTa)Sb (without charge order). In the bulk of RbVSb (>33 nm from the surface), we observed an increase in the internal magnetic field width in the charge-ordered state. Near the surface (<33 nm), the muon spin relaxation rate is significantly enhanced and this effect commences at temperatures significantly higher than the onset of charge order. In contrast, no similar field width enhancement was detected in Cs(VTa)Sb, either in the bulk or near the surface. These observations indicate a strong connection between charge order and TRS breaking and suggest that TRS breaking can occur prior to long-range charge order.
在戈薇超导体AVSb的正常态中，时间反演对称性（TRS）的破缺是一个显著特征，但其可调性尚未得到研究。我们使用低能μ子自旋旋转和局部场数值分析，研究了RbVSb（具有电荷序）和Cs(VTa)Sb（不具有电荷序）单晶中TRS破缺随深度的变化。在RbVSb的体相中（距表面>33nm），我们观察到电荷有序态下内部磁场宽度增加。在表面附近（<33nm），μ子自旋弛豫率显著增强，且这种效应在远高于电荷序起始温度时就开始出现。相比之下，在Cs(VTa)Sb的体相或表面附近均未检测到类似的场宽增强。这些观察结果表明电荷序与TRS破缺之间存在紧密联系，并表明TRS破缺可能在长程电荷序之前发生。
