Fig. 1: Crystal structure, tight-binding calculations and FS.

a Crystal structure of CoSn with space group P6/mmm (No. 191). b High-resolution STM topography with V = 1 V, I = 20 pA. Co₃Sn surface (blue) and Sn surface (black) are indicated. c Atomic-resolved STM topography on Co₃Sn plane with V = 500 mV, I = 100 pA. d The typical kagome band is produced by using the tight-binding method with single-orbital nearest-neighbor hopping. The black (red) curves are indicated for with (without) the inclusion of SOC. e 3D bulk BZ with marked high-symmetry points and two mirror planes: σ_h (Γ−K−M) and σ_v (Γ−A−H−K). \(\bar{\Gamma }-\bar{K}-\bar{M}\) plane is a projected 2D BZ. f Intensity plot at E_F ± 10 meV in 2D BZ. The red lines indicate high-symmetry directions and the first BZ projected on the (001) surface.