Diverse Electronic Landscape of the Kagome Lattice

Quantum materials with a kagome lattice—comprising corner-sharing triangles that form hexagonal motifs within the crystal structure—have emerged as ideal platforms to explore the interplay among geometry, topology, electronic correlations, magnetism, and charge order. A recently discovered family of kagome metals with the formula ReTi₃Bi₄ (Re = rare earth) has attracted considerable attention due to its combination of highly anisotropic magnetism and complex electronic structure. Using angle-resolved photoemission spectroscopy (ARPES) measurements in conjunction with density functional theory (DFT) calculations, we investigate the electronic structure of these newly identified kagome metals. Our results reveal the presence of multiple van Hove singularities (VHSs), several of which lie in close proximity to the Fermi level. We also observe distinct flat bands originating from destructive interference of electronic wave functions within the Ti-based kagome network. These flat bands and VHSs, derived primarily from Ti d-orbitals, exhibit pronounced sensitivity to the polarization of the incident beam. Overall, our findings demonstrate that the Ti-based kagome material system represents an excellent platform for investigating kagome-induced flat band physics and its intricate connection to magnetism.