Three-dimensional higher-order saddle-point-induced flatbands in Co-based kagome metals
Published in Physical Review Research, 2024
Abstract: We report the discovery of two types of three-dimensional higher-order saddle points (HOSPs) in Co-based kagome metals. Both HOSPs display a strongly enhanced density of states compared to conventional 2D Van Hove singularities, and one HOSP located near the Fermi level generates an extended flatband across a large region of the Brillouin zone.