Thermally reconfigurable topological protection routes for the 2D phononic system

Abstract

Tunable topological insulators (TIs) with active tunability of frequency or path and better adaptability to the dynamic environment than conventional TIs have attracted great interest recently. The research directions of tunable TIs are mainly in the frequency domain and spatial domain. However, the most current research is mainly based on the former. Obviously, the tunable spatial path can bring more degrees of freedom to the application of TIs. Here, we present a topological protection system realized by a thermally tunable elastic film composed of VO2 covered on a patterned substrate. The topological phase transition is induced by breaking the symmetry of the unit cell on the substrate, and we pre-define the topological protection paths in each direction on the substrate. The conduction or blocking of elastic waves is achieved by using the metal-insulator phase transition of VO2, which enables intelligent TIs with reconfigurable propagation paths and reconfigurable interfaces. In addition, the reconfigurable topological path and the thermal modulation are presented by numerical simulations. Such elastic topological materials and their corresponding devices will significantly promote the development of TIs and are expected to enable the coupling with communication band electromagnetic waves and the realization of light-induced non-contact thermal modulation.