Evidence for time-reversal symmetry-breaking kagome superconductivity

• Main Authors: 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
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2025
• Subjects: Physics; Superconductivity and magnetism; Time reversal symmetries
• Online Access: https://hdl.handle.net/10356/182714
• Institution: Nanyang Technological University

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)3Sb5, 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.