Tunable elastic topological insulators based on bicomponent perforated structures

Abstract

In this paper, a tunable elastic topological insulator based on bicomponent is designed. We rotate the perforated structure of the mixed components in two different ways, local and global, to reduce the structural symmetry of the lattice and obtain the elastic topological insulator. By introducing a mixed-component perforated structure with a certain rotation angle into the primitive cell, the symmetry is incomplete and the quadruple degenerate state is constructed. When locally rotating mixed component perforated structure, the quadruple degenerate state is separated and reversed at point, and we can get a structure with topological properties. In addition, without re-constructing the perforated structure parameters of the unit cell, when the mixed component perforated structure is rotated as a whole, we can also realize the elastic topological insulator, and its non-trivial band gap is widened by about three times. Finally, we verify the transport properties of the topological boundary states of the elastic topological insulator by both numerical simulations and experimental tests.