Acoustic Topological Transport and Refraction in a Kekulé Lattice

Acoustic topological insulators can yield directional antennas for sound, enabling energy-efficient communication. This study explores using the interface-dependent spin Hall or valley Hall -like transport in a Kekul\'e lattice to generate directed beams: one, two in symmetric or antisymmetric fashion, or multiple beams. This topological refractive system could serve as an acoustic beam splitter, offering the advantages of stability, efficiency, and parity control.