Reconfigurable topologically protected wave propagation in metastable structure

Abstract

In this paper, topologically protected wave propagation in metastable structure has been investigated by mimicking the quantum valley Hall effect. Reconfigurable topological waveguides are achieved by switching the metastable states of the structure. First, a K-point Dirac cone, which is guaranteed by the C6 rotational symmetry of the metastable unit cell, is identified in the band structure. Then, by reconfiguring the bistable elements, the space inversion symmetry of the unit cell is broken and a topological bandgap opened. The topological non-triviality of this bandgap is verified by the values assumed by the Berry curvature and valley Chern number. Next, the topological edge modes localized at the interface are studied by analyzing the dispersion relation of a finite strip. The analysis results show that reconfigurable topologically protected waveguides, which are immune to backscattering at sharp corners and local defects, can be achieved utilizing the edge modes.