The interaction of topology, magnetism, and correlations leads to fascinating phases of matter. In this research, we use angle-resolved photoemission spectroscopy, density functional theory, and dynamical mean-field theory calculations to reveal a fourfold degenerate Dirac nodal line at the boundary of the bulk Brillouin zone in the antiferromagnet YMn2Ge2. We show that this gapless, antiferromagnetic Dirac nodal line arises from the combination of magnetism, space-time inversion symmetry, and nonsymmorphic lattice symmetry. The related drumhead surface states span the entire surface Brillouin zone. Thus, YMn2Ge2 serves as a platform to explore the interplay of multiple degenerate nodal physics and antiferromagnetism. Notably, the magnetic nodal line exhibits a d-orbital dependent renormalization, highlighting the influence of Hund's coupling. Our results provide insights into how electronic correlations affect magnetic Dirac nodal lines, resulting in an antiferromagnetic Hund nodal line.
*Advanced ARPES and theoretical work at Princeton University were supported by the US DOE under the Basic Energy Sciences program (grant number DOE/BES DE-FG-02-05ER46200; M.Z.H.), NQI at ORNL_Quantum Science Center supported by US DOE and the Gordon and Betty Moore Foundation (GBMF4547 and GBMF9461; M.Z.H.). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515.
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Publication:Xian P. Yang, Yueh-Ting Yao, Pengyu Zheng, Shuyue Guan, Huibin Zhou, Tyler A. Cochran, Che-Min Lin, Jia-Xin Yin, Xiaoting Zhou, Zi-Jia Cheng, Zhaohu Li, Tong Shi, Md Shafayat Hossain, Shengwei Chi, Ilya Belopolski, Yu-Xiao Jiang, Maksim Litskevich, Gang Xu, Zhaoming Tian, Arun Bansil, Zhiping Yin, Shuang Jia, Tay-Rong Chang & M. Zahid Hasan. A topological Hund nodal line antiferromagnet. Nature Communications volume 15, Article number: 7052 (2024).
