Spectroscopic tunability of kagome magnet Fe₃Sn₂ thin films by magnetic field

Kagome materials, named after the corner-sharing hexagonal lattice structure, provide an excellent platform to study topological and correlated electronic states. Kagome magnet Fe₃Sn₂ exhibits or has been theoretically predicted to exhibit many exotic quantum states, including flatbands, massive Dirac fermions, giant spin-orbit tunability, helical nodal lines and switchable Weyl points. Among these phenomena, experimental evidence for the existence of switchable Weyl points has been difficult to achieve. We use molecular beam epitaxy to grow Fe₃Sn₂ thin films and identify the Fe₃Sn₂ phase from diffraction and magnetization measurements. Using scanning tunneling microscopy/spectroscopy, we observe multiple peaks in differential conductance (dI/dV) spectra around the Fermi level. The peaks disperse in energy when an out-of-plane magnetic field is applied. We discuss these observations in the context of Weyl points theoretically predicted to occur in this system in the vicinity of the Fermi level.