2014/01/25 by Xueqin Huang, Huang, Xueqin, Meng Xiao +5
Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Optics (physics.optics) #cond-mat.mes-hall #physics.optics
paper · pdf · doi:10.48550/arxiv.1401.6554
arxiv created 2014/01/25 · arxiv updated 2014/01/28
There is no assurance that interface states can be found at the boundary separating two materials. As a strong perturbation typically favors wave localization, it is natural to expect that an interface state should form more easily in the boundary that represents a strong perturbation. Here, we show on the contrary that in some two dimensional photonic crystals (PCs) with a square lattice possessing Dirac-like cone at k=0, a small perturbation guarantees the existence of interface states. More specifically, we find that single-mode localized states exist in a deterministic manner at an interface formed by two PCs each with system parameters slightly perturbed from the conical dispersion condition. The conical dispersion guarantees the existence of gaps in the projected band structure which allows interface states to form and the assured existence of interface states stems from the geometric phases of the bulk bands.