Probing the temperature dependence of the electronic structure of kagome magnet FeSn thin film

Quantum solids consisting of the kagome lattice have recently stimulated a surge of interest owing to the rich landscape of quantum phases, potentially driven by the inherent Dirac band crossings, Van Hove singularities and topological flat bands. Magnetic kagome materials provide a fascinating playground for exploring the interplay of magnetism, correlation and topology. While partially filling a kagome flat band is predicted to give rise to a Stoner-type ferromagnetism, experimental visualization of the magnetic splitting across the ordering temperature has been lacking. Here, we probe the electronic structure with angle-resolved photoemission spectroscopy in a kagome magnet thin film FeSn synthesized using molecular beam epitaxy. We identify the signature kagome band structure, consistent with density functional theory calculations that exhibit an exchange splitting in the antiferromagnetic phase. We study the temperature dependence of the band structure from cryogenic temperature to above the Neel temperature of 370 K. We further reveal intriguing correlation effects in the electronic structure. We will discuss the implications of our findings on magnetism and correlation effects in kagome magnet FeSn thin film.