Fig. 1: Atomic and electronic structure of Kondo kagome system YbCr6Ge6 (YCG).
From: Coexisting kagome and heavy fermion flat bands in YbCr6Ge6
a Atomic structure of the kagome lattice system YCG, delineating the layered arrangement of Yb, Cr, and Ge. b Kagome layer composed of Cr atoms. c Honeycomb Ge layer with Yb atoms situated at the hexagonal centers. d Honeycomb Ge layer with perpendicular Ge dimers at the hexagonal centers. Schematic illustrations of the Cr kagome bands and localized Yb f-orbitals e without hybridization, f in DFT, and g DFT+DMFT, respectively. The Dirac point (DP), van Hove singularities saddle point (SP), and KFB are highlighted. LS and KRS represent localized states and Kondo resonance states of Yb f-orbitals, respectively. h Brillouin zone (BZ) showing the high-symmetry points used in calculations. i–k DFT Band structures projected onto the f orbitals (red), Cr \(3{d}_{{z}^{2}}\) orbitals (blue), and Cr \({d}_{{x}^{2}-{y}^{2}}/{d}_{xy}\) (green), respectively, obtained with U = 0 for both Cr d and Yb f orbitals. The zero-energy level is set at the charge-neutral electron filling.
