Line of Dirac Nodes in Hyperhoneycomb Lattices
Line of Dirac Nodes in Hyperhoneycomb Lattices
We propose a family of free fermion lattice models that have "Dirac loops", closed lines of Dirac nodes in momentum space, on which the density of states vanishes linearly with energy. Those lattices all possess the planar trigonal connectivity present in graphene, but are three dimensional. We show that their …