Atomic Layer Molecular Beam Epitaxy of Kagome Magnet RMn_6Sn_6 (R = Er, Tb) Thin Films

Kagome lattices have garnered substantial interest because their band structure consists of topological flat bands and Dirac cones. The RMn_6Sn_6 (R = rare earth) compounds are particularly interesting because of the existence of large intrinsic anomalous Hall effect (AHE) which originates from the gapped Dirac cones near the Fermi level. This makes RMn_6Sn_6 an outstanding candidate for realizing the high-temperature quantum anomalous Hall effect. The growth of RMn_6Sn_6 thin films is beneficial for both fundamental research and potential applications. However, most of the studies on RMn_6Sn_6 have focused on bulk crystals so far, and the synthesis of RMn_6Sn_6 thin films has not been reported so far. Here we report the atomic layer molecular beam epitaxy growth, structural and magnetic characterizations, and transport properties of ErMn_6Sn_6 and TbMn_6Sn_6 thin films. It is especially noteworthy that TbMn_6Sn_6 thin films have out-of-plane magnetic anisotropy, which is important for realizing the quantum anomalous Hall effect. Our work paves the avenue toward the control of the AHE using devices patterned from RMn_6Sn_6 thin films.