Recent Progress on 2D Kagome Magnets: Binary TmSnn (T = Fe, Co, Mn)

Due to the particularity of the lattice geometry, intriguing electronic characteristics of Dirac cone and flat band can coexist in the two-dimensional (2D) kagome lattice. The 2D kagome materials, therefore, have attracted tremendous attention, as a platform for studying the topological non-trivial band structures and strong correlated phenomena. In this paper, the recent experimental progress on binary kagome metals Fe3Sn2, FeSn, CoSn, and Mn3Sn, mainly by the methods of scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), and angle-resolved photoemission spectroscopy (ARPES), are reviewed. In those compounds, the kagome layers give rise to the electronic structure of flat bands and Dirac cones, which induce a wide range of novel electron behaviors. Their exposed surface structure, electronic band structure, and topological properties are therefore highlighted, aiming at illustrating the determining role of their 2D kagome layers. In addition, the interplay between frustrated kagome geometry, frustrated magnetism, and topological magnetism, which brings new opportunities and broad prospects to the research of strongly correlated topological kagome magnetic materials, is introduced through reviewing recent experimental works by electronic and magnetic transport measurements.