Deng Hanbin, Liu Guowei, Guguchia Z, Yang Tianyu, Liu Jinjin, Wang Zhiwei, Xie Yaofeng, Shao Sen, Ma Haiyang, Liège William, Bourdarot Frédéric, Yan Xiao-Yu, Qin Hailang, Mielke C, Khasanov R, Luetkens H, Wu Xianxin, Chang Guoqing, Liu Jianpeng, Christensen Morten Holm, Kreisel Andreas, Andersen Brian Møller, Huang Wen, Zhao Yue, Bourges Philippe, Yao Yugui, Dai Pengcheng, Yin Jia-Xin
Department of Physics, Southern University of Science and Technology, Shenzhen, China.
Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, Villigen PSI, Aargau, Switzerland.
Nat Mater. 2024 Dec;23(12):1639-1644. doi: 10.1038/s41563-024-01995-w. Epub 2024 Aug 28.
Superconductivity and magnetism are often antagonistic in quantum matter, although their intertwining has long been considered in frustrated-lattice systems. Here we utilize scanning tunnelling microscopy and muon spin resonance to demonstrate time-reversal symmetry-breaking superconductivity in kagome metal Cs(V, Ta)Sb, where the Cooper pairing exhibits magnetism and is modulated by it. In the magnetic channel, we observe spontaneous internal magnetism in a fully gapped superconducting state. Under the perturbation of inverse magnetic fields, we detect a time-reversal asymmetrical interference of Bogoliubov quasi-particles at a circular vector. At this vector, the pairing gap spontaneously modulates, which is distinct from pair density waves occurring at a point vector and consistent with the theoretical proposal of an unusual interference effect under time-reversal symmetry breaking. The correlation between internal magnetism, Bogoliubov quasi-particles and pairing modulation provides a chain of experimental indications for time-reversal symmetry-breaking kagome superconductivity.
在量子物质中，超导性和磁性通常是相互对立的，尽管它们的相互交织在受挫晶格系统中早已被考虑。在这里，我们利用扫描隧道显微镜和μ子自旋共振来证明在 Kagome 金属 Cs(V, Ta)Sb 中存在时间反演对称性破缺的超导性，其中库珀对表现出磁性并受其调制。在磁性通道中，我们在完全能隙的超导态中观察到自发的内禀磁性。在反向磁场的扰动下，我们在一个圆矢量处检测到玻戈留波夫准粒子的时间反演不对称干涉。在这个矢量处，配对能隙自发调制，这与在点矢量处出现的对密度波不同，并且与时间反演对称性破缺下异常干涉效应的理论提议一致。内禀磁性、玻戈留波夫准粒子和配对调制之间的相关性为时间反演对称性破缺的 Kagome 超导性提供了一系列实验证据。
