Max-Planck Institute for Chemical Physics of Solids, Dresden, Germany

Abstract:

Magnetic topological materials host extraordinary phenomena including the quantum anomalous Hall effect, Weyl states with topological Fermi arcs, and axion or higher-order topological phases - all arising from the intricate interplay between electronic band topology and magnetic order, positioning them as ideal platforms for quantum technologies and energy-efficient spintronics. In this talk, I will demonstrate how strong electron-magnetic coupling - mediated by Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between itinerant electrons and localized magnetic moments - dramatically enhances anomalous transport while reconstructing fundamental electronic band structures. As a paradigmatic example, we investigate the kagome magnet TbTi₃Bi₄, where neutron diffraction, spin-polarized STM, and ARPES reveal a remarkable coexistence of elliptical spiral magnetic order, spin-density waves, and an unusually large band-folding gap (~90 meV). This unique combination of electronic and magnetic properties produces a record-high anomalous Hall conductivity of 105 Ω⁻¹cm⁻¹, surpassing all known frustrated kagome systems. Our findings establish strong electron-magnetic coupling as a powerful design principle for discovering exotic quantum phases and engineering next-generation topological materials with tailored functionalities.

Resume:

Dr. Erjian Cheng received his Ph.D. degree from the Fudan University in 2021. He was an Alexander von Humboldt Research fellow at the Max-Planck Institute for Chemical Physics of Solids, Dresden, Germany, and become a group leader in Prof. Claudia Felser’s group at the Max-Planck Institute for Chemical Physics of Solids. His interests lie in topological systems, mostly focusing on the magnetic topological systems.

邀请人：刘恩克（82649085，ekliu@iphy.ac.cn）