Lazarides N, Tsironis G P
Department of Physics, University of Crete, P. O. Box 2208, 71003 Heraklion, Greece.
National University of Science and Technology "MISiS", Leninsky Prospekt 4, Moscow, 119049 Russia.
Sci Rep. 2019 Mar 20;9(1):4904. doi: 10.1038/s41598-019-41155-8.
The conditions leading to flat dispersionless frequency bands in truly one-dimensional parity-time () symmetric metamaterials comprised of split-ring resonators (SRRs) arranged in a binary pattern are obtained analytically. In this paradigmatic system, in which the SRRs are coupled through both electric and magnetic dipole-dipole forces, flat-bands may arise from tailoring its natural parameters (such as, e.g., the coupling coefficients between SRRs) and not from geometrical effects. For sets of parameters which values are tailored to flatten the upper band of the spectrum, the solution of the corresponding quadratic eigenvalue problem reveals the existence of compact, two-site localized eigenmodes. Numerical simulations confirm the existence and the dynamic stability of such modes, which can be formed through the evolution of single-site initial excitations without disorder or nonlinearity.
通过解析方法得到了由呈二元图案排列的裂环谐振器（SRR）构成的真正一维宇称时间（）对称超材料中导致平坦无色散频带的条件。在这个典型系统中，SRR通过电偶极子力和磁偶极子力耦合，平坦频带可能源于对其固有参数（例如SRR之间的耦合系数）的调整，而非几何效应。对于为使频谱的上频带平坦而调整参数值的参数集，相应二次特征值问题的解揭示了紧凑的双位点局域本征模的存在。数值模拟证实了这些模式的存在及其动态稳定性，它们可以通过单位点初始激发的演化在没有无序或非线性的情况下形成。
