Line nodes, Dirac points, and Lifshitz transition in two-dimensional nonsymmorphic photonic crystals
Line nodes, Dirac points, and Lifshitz transition in two-dimensional nonsymmorphic photonic crystals
Topological phase transitions, which have fascinated generations of physicists, are always demarcated by gap closures. In this work, we propose very simple 2D photonic crystal lattices with gap closure points, i.e. band degeneracies protected by nonsymmorphic symmetry. Our photonic structures are relatively easy to fabricate, consisting of two inequivalent dielectric …