The paper presents interesting studies on tunable higher-order topological states of acoustic systems. A 3D structure based on an in-plane Kagome lattice and an out-of-plane Su-Schrieffer-Heeger chain is proposed, that by engineering couplings in different dimensions can simultaneously host 2D surface states, 1D hinge states and 0D corner states.
- Yuexin Zhang
- Jie Tang
- Yuanjiang Xiang
