First-principles study of Dirac and Dirac-like cones in phononic and photonic crystals
First-principles study of Dirac and Dirac-like cones in phononic and photonic crystals
By using the \vec{k}\cdot\vec{p} method, we propose a first-principles theory to study the linear dispersions in phononic and photonic crystals. The theory reveals that only those linear dispersions created by doubly-degenerate states can be described by a reduced Hamiltonian that can be mapped into the Dirac Hamiltonian and possess a …