Group Theoretical Route to Deterministic Weyl Points in Chiral Photonic Lattices

Abstract

Topological phases derived from point degeneracies in photonic bandstructures show intriguing and unique behaviour. Previously identified band degeneracies are based on accidental degeneracies and subject to engineering on a case-by-case basis. Here we show that deterministic pseudo Weyl points with non-trivial topology and hyper-conic dispersion exist at the Brillouin zone center of chiral cubic symmetries. This conceivably allows realization of topologically protected frequency isolated surface bands in 3D and n = 0 properties as demonstrated for a nano plasmonic system and a photonic crystal.