Simple Chemical Rules for Predicting Band Structures of Kagome Materials

Compounds featuring a kagome lattice
are studied for a wide range
of properties, from localized magnetism to massless and massive Dirac
Fermions. These properties come from the symmetry of the kagome lattice,
which gives rise to Dirac cones and flat bands. However, not all compounds
with a kagome sublattice show properties related to it. We derive
chemical rules predicting if the low-energy physics of a material
is determined by the kagome sublattice and bands arising from it.
After sorting out all known crystals with the kagome lattice into
four groups, we use chemical heuristics and local symmetry to explain
additional conditions that need to be met to have kagome bands near
the Fermi level.