Observation of Low-Energy Saddle Points, Dirac nodes and Weakly Dispersive Bands in Distorted Ti-based Kagome Metal

Compounds hosting kagome lattices show tremendous variety of energetic orderings of their characteristic Dirac nodes, saddle-point Van Hove singularities, and flat bands. The proximity of these features of the electronic structure to the Fermi energy can enhance phenomena such as charge density waves, superconductivity, and the anomalous Hall effect. The discovery of a new family of Ti-based kagome lattice compounds, with stoichiometry LnTi3Bi4, introduces the influence of a small orthorhombic distortion to the conventional kagome lattice in addition to the influence of tunable lanthanide element. Here, we report the electronic structure of a new LnTi3Bi4 compound, as obtained through angle-resolved photoemission spectroscopy and density functional theory calculations. Electronic bands derived from the kagome Dirac nodes and Van Hove singularities are found close to the experimental Fermi energy. Additionally, we discuss the dispersion characteristics of weakly dispersing kagome “flat” bands as induced by the orthorhombic distortion and interlayer interactions.