studied by ARPES*

Recent discoveries in magnetic RMn₆Sn₆ compounds (R=rare earth element) have opened a new path toward topological state engineering [1,2]. Topological states found in these compounds’ electronic structure are the result of both lattice geometry and electronic correlations. Interactions between Mn 3d electrons arranged in a kagome lattice, and 4f electrons from R atoms act as a source of a Chern gap and massive Dirac fermions. The size of the Chern gap and magnetic order in RMn₆Sn₆ can be manipulated by changing the R atom type. Different types of magnetic anisotropy are observed: easy ab-plane for Dy, easy c-axis for Tb and a conical magnetic structure for Ho and Dy.

Here, we present studies of the electronic structure of HoMn₆Sn₆ by means of angle resolved photoelectron spectroscopy (ARPES) at low temperature (~7 K). Our results show that the electronic structure of this system is three-dimensional, with significant dispersion along c-axis. We have observed a band structure typical of a topological kagome metal:  Dirac cones at K points and flat bands at M points. We find that the Dirac points are located very close to the Fermi level. Additionally, we resolved the electron band around the Γ point, which shows an enhanced effective mass. We will discuss the influence of electronic correlations, originating mostly from Ho atoms, on the topological states.

[1] J.-X. Yin et al., Nature 583, 533 (2020).

[2] W. Ma et al., Phys. Rev. Lett. 126, 246602 (2021).