Molecular beam epitaxy growth and Scanning Tunneling Microscope study of FeSn-type kagome metals

The two-dimensional kagome lattice combines a flat band and a Dirac point in its electronic structure which could give rise to strongly correlated and topological electronic states. The FeSn-type compounds in which transition metal atoms form a layered lattice structure have recently emerged as a model kagome system. Owing to the reduced interlayer coupling between the individual kagome planes, the near ideal kagome electronic states provide a rich platform to explore the interplay of topology, magnetism, and strong electronic correlations.

We use molecular beam epitaxy to realize high-quality FeSn and CoSn thin film samples on the surface of STO(111). Optimizing the epitaxial growth procedure, we can adapt the growth mode from island growth to continuous film growth and fabricate different sample types for different characterization methods. Introducing a Pt(111) buffer layer on Al2O3(0001), we further implement a controlled layer-by-layer growth mode. We combine scanning tunneling microscopy and electron transport measurements to characterize the material properties and demonstrate the high film quality.

Our work opens avenues for the study of FeSn-type compounds using microscopic and macroscopic measurement techniques, and for the realization of new kagome heterostructures using layer-by-layer growth.