Owing to the unusual geometry of kagome lattices, their electrons are useful for studying the physics of frustrated, correlated and topological quantum electronic states. In the presence of strong spin–orbit coupling, the magnetic and electronic structures of kagome lattices are further entangled, which can lead to hitherto unknown spin–orbit phenomena. In this talk, I will discuss two of the kagome magnets we studied, Mn₃Sn and Fe₃Sn₂, using a scanning tunneling microscopy with a vector-magnetic- field capability and temperature control.
Mn₃Sn is a strongly correlated antiferromagnet consisting of only kagome layers. We observe a pronounced resonance with a Fano line shape at the Fermi level resembling the Kondo resonance previously observed in some f-electron materials. The magnetic field and temperature dependence indicate its strongly interacting nature. Our new results uncover the emergent many-body resonance behavior in an antiferromagnetic topological material but without f-electrons.
Fe₃Sn₂ is a ferromagnet containing a kagome bilayer. We discover that its many-body electronic state couples strongly to the vector field with three-dimensional anisotropy, exhibiting a giant nematic energy shift. We further manipulate the nematicity with our vector magnetic field due to its giant spin-driven electronic responses, which points to the realization of an underlying correlated magnetic topological phrase. It provides new ways of controlling spin-orbit properties and exploring emergent phenomena in topological quantum materials [1].
[1] Yin, J., Zhang, S.S. et al. Nature 562, 91–95 (2018).