Persistent flat band splitting and strong selective band renormalization in a kagome magnet thin film
arXiv:2410.06147 · doi:10.1038/s41467-024-53722-3
Abstract
Magnetic kagome materials provide a fascinating playground for exploring the interplay of magnetism, correlation and topology. Many magnetic kagome systems have been reported including the binary FemXn (X=Sn, Ge; m:n = 3:1, 3:2, 1:1) family and the rare earth RMn6Sn6 (R = rare earth) family, where their kagome flat bands are calculated to be near the Fermi level in the paramagnetic phase. 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 not been reported for any of these systems due to the high ordering temperatures, hence leaving the nature of magnetism in kagome magnets an open question. 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 exchange-split kagome flat bands, whose splitting persists above the magnetic ordering temperature, indicative of a local moment picture. Such local moments in the presence of the topological flat band are consistent with the compact molecular orbitals predicted in theory. We further observe a large spin-orbital selective band renormalization in the Fe d_xy+d_(x^2-y^2 ) spin majority channel reminiscent of the orbital selective correlation effects in the iron-based superconductors. Our discovery of the coexistence of local moments with topological flat bands in a kagome system echoes similar findings in magic-angle twisted bilayer graphene, and provides a basis for theoretical effort towards modeling correlation effects in magnetic flat band systems.
References in corpus (40)
- High temperature fractional quantum Hall states
- CsVSb: a topological kagome metal with a superconducting ground state
- Discovery of unconventional chiral charge order in kagome superconductor KV3Sb5
- Quantum Monte Carlo Impurity Solver for Cluster DMFT and Electronic Structure Calculations in Adjustable Base
- Cascade of correlated electron states in a kagome superconductor CsV3Sb5
- Discovery of a quantum limit Chern magnet TbMn6Sn6
- Unconventional Fermi surface instabilities in the Kagome Hubbard Model
- Wannier representation of Z_2 topological insulators
- Hybridization expansion impurity solver: General formulation and application to Kondo lattice and two-orbital models
- Discovery of charge density wave in a correlated kagome lattice antiferromagnet
- The coherence-incoherence crossover and the mass-renormalization puzzles in Sr2RuO4
- Orbital-Selective Mott transition out of band degeneracy lifting
- MATBG as Topological Heavy Fermion: I. Exact Mapping and Correlated Insulators
- Rotation symmetry breaking in the normal state of a kagome superconductor KV3Sb5
- How bad metals turn good: spectroscopic signatures of resilient quasiparticles
- Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in AFeSe (A=K, Rb) Superconductors
- Entropic evidence for a Pomeranchuk effect in magic angle graphene
- Charge density wave in kagome lattice intermetallic ScV6Sn6
- Intertwined magnetism and charge density wave order in kagome FeGe
- Orbital-selective Mott Phase in Multiorbital Models for Alkaline Iron Selenides K(1-x)Fe(2-y)Se2
- Fractional power-law behavior and its origin in iron-chalcogenide and ruthenate superconductors: Insights from first-principles calculations
- Observation of Flat Band, Dirac Nodal Lines and Topological Surface States in Kagome Superconductor CsTiBi
- Kinetic ferromagnetism on a kagome lattice
- Spin excitations in metallic kagome lattice FeSn and CoSn
- Electronic nematicity without charge density waves in titanium-based kagome metal
- Phonon promoted charge density wave in topological kagome metal ScVSn
- Non-Thermal Emergence of an Orbital-Selective Mott Phase in FeTeSe
- Correlation-Driven Electronic Reconstruction in FeTeSe
- Tunable van Hove singularity without structural instability in Kagome metal CsTiBi
- Plethora of tunable Weyl fermions in kagome magnet Fe3Sn2 thin films
- Nanoscale visualization and spectral fingerprints of the charge order in ScV6Sn6 distinct from other kagome metals
- Coupled topological flat and wide bands: Quasiparticle formation and destruction
- Anomalous quasiparticles in the zone center electron pocket of the kagomé ferromagnet Fe3Sn2
- Spin-polarized imaging of the antiferromagnetic structure and field-tunable bound states in kagome magnet FeSn
- Complex magnetic and spatial symmetry breaking from correlations in kagome flat bands
- Visualizing symmetry-breaking electronic orders in epitaxial Kagome magnet FeSn films
- Chiral and flat-band magnetic cluster excitations in a ferromagnetic kagome metal
- Topological Electronic Structure Evolution with Symmetry Breaking Spin Reorientation in (FeCo)Sn
- Catalogue of Flat-Band Stoichiometric Materials
- Imaging real-space flat band localization in kagome magnet FeSn