Anisotropic behavior of plasmons in kagome metal YCr6Ge6

We report on the growth of YCr6Ge6, which crystalizes in the hexagonal crystal structure with Cr atoms adopting a kagome lattice. The plasmon dispersion of YCr6Ge6 was investigated with momentum resolved electron energy loss spectroscopy revealing an anisotropic behavior along the [101̄0] (in-plane) and [0001] (out-of-plane) propagating directions. Group velocities are one order of magnitude smaller than those in traditional free-electron gas metals. Damping processes occur within the particle–hole continuum band. This study provides insights into the role of complex band structure in the plasmon behavior of kagome metals and alternatives in the search for new plasmonic materials.