Tunable and Reconfigurable Higher‐Order Topological Insulators in Photonic Crystals with Phase Change Materials

Abstract

Abstract Higher‐order topological insulators (HOTIs) have attracted great interest due to the unconventional bulk‐boundary correspondence. However, the realization of HOTIs usually requires a geometrical transformation of the photonic crystals (PhCs), setting high demands on the manufacturing process. Here a scheme is reported of tunable and reconfigurable HOTIs with phase change materials (PCMs) by controlling the temperature. The temperature change can transform the amorphous states to crystalline states, leading to the reconfigurable edge states and corner states. It is proven that both Sb 2 S 3 and Sb 2 Se 3 can support the reconfigurable HOTIs at the phase change temperature 270 °C at different wavelengths. This work discovers a new platform for the practical implementation of high‐order topological phase transition optical apparatus in the foreseeable future, such as nanocavities, waveguides, and metasurfaces.