Topological Slot in Phononic Crystals.

The hallmark of Chern insulators is the unidirectional propagation of chiral edge states, which are immune to imperfections due to bulk topological protection. However, this robustness presents a fundamental challenge in pausing or spatially confining these information carriers on demand. Here, we propose a topological slot that enables spatial trapping and controlled release of these chiral modes. The trapping occurs at the interface between two topological domains that share the same Chern number but exhibit a polarization mismatch. We implement the topological slot in phononic crystals and directly observe acoustic waves that propagate or become trapped under different slot configurations. The proposed topological slot provides a new route to manipulating topological states and may provide a pathway toward topological information storage and encoding.