Fig. 2. First-principles analysis of Sc-Herbertsmithite.

a Top view of the crystal structure, where the CuO₄ plaquettes form a Kagome lattice, as highlighted by the orange lines. b Ab-initio band structure of the low-energy manifold of Sc-Herbertsmithite along the high-symmetry directions of the conventional hexagonal Brillouin zone²¹. The dashed black lines refer to a linear fit around the Dirac point of Sc-Herbertsmithite, whereas the solid gray lines denote the counterpart for graphene. c Phonon dispersion of Sc-Herbertsmithite (gray lines) and relative distribution of the electron-phonon coupling strengths λ_νq (blue circles, ν is the branch index, q the phonon momentum). The horizontal dashed line marks the temperature T_ph above which optical phonon modes with sizeable λ_νq are thermally activated.