Tunneling into topological magnets: discovery of Chern and many-body phenomena*

Tunneling into topological magnets: discovery of Chern and many-body quantum phenomena

The search for topological phases of matter is evolving towards magnetic systems, where exotic effects emerge from the quantum level interplay between geometry, correlation, and topology. Equipped with unprecedented spatial resolution, electronic detection, and magnetic tunability, scanning tunneling microscopy (STM) has become a powerful tool to probe and discover topological magnet. Via spectroscopic Landau quantization and edge state imaging, we discover the Chern phase in TbMn6Sn6 [1]. Through quasi-particle interferences based on vectorial magnetization, we discover giant and anisotropic spin-orbit tunability in Fe3Sn2 [2]. Using spin-polarized or magnetization polarized STM, we observe flat band orbital magnetism and spin-orbit quantum impurity in a Co-based magnet [3,4]. We also uncover many-body resonance in an Mn-based antiferromagnet [5] and many-body fermion-boson interplay in a Co-based paramagnet [6]. These research developments not only demonstrate STM's ability to discover interacting topological phenomena but also allow researchers to connect to the results obtained by other techniques including angle-resolved photoemission, magneto-transport, density functional and tight-binding modeling.

1. J-X Yin et al. Nature 583, 533 (2020).
2. J-X Yin et al. Nature 562, 91-95 (2018).
3. J-X Yin et al. Nature Physics 15, 443 (2019).
4. J-X Yin et al. Nat Commun 11, 4415 (2020).
5. S. S. Zhang et al. Phys. Rev. Lett. 125, 046401 (2020).
6. J-X Yin et al. Nat Commun 11, 4003 (2020).

These studies are in collaboration with M. Zahid Hasan, Songtian S. Zhang, Shuang Jia, Wenhong Wang, Hechang Lei, Satoru Nakatsuji, Ziqiang Wang, Titus Neupert, Hsin Lin, Guoqing Chang, Tay-Rong Chang, Biao Lian, Brian Møller Andersen, and Rui Wang.