  Theory anticipates that the in-plane px, py orbitals in a honeycomb lattice
lead to new and potentially useful quantum electronic phases. So far, p orbital
bands were only realized for cold atoms in optical lattices and for light and
exciton-polaritons in photonic crystals. For electrons, in-plane p orbital
physics is difficult to access since natural electronic honeycomb lattices,
such as graphene and silicene, show strong s-p hybridization. Here, we report
on electronic honeycomb lattices prepared on a Cu(111) surface in a scanning
tunneling microscope that, by design, show (nearly) pure orbital bands,
including the p orbital flat band and Dirac cone.
