Chiral anomaly bulk states in acoustic S-graphene with multiple Dirac points

Abstract

Dirac points (DPs) lie at the core of topological physics. Beyond robust in-gap edge states, chiral-anomaly bulk states (CABSs) induced by finite-size effects enable resilient bulk transport. Extending CABS research from systems with a single DP pair to those with multiple pairs introduces additional degrees of freedom and richer transport phenomena. Here, we investigate the CABSs in finite-size acoustic S-graphene systems containing two distinct pairs of DPs. We show that sample-size tuning yields CABSs with diverse dispersion slopes. Leveraging both dispersion types and symmetry properties of these CABSs enables precisely controlled directional bulk radiation with quantized branch multiplicities. These results expand the classification of CABS dispersion relations, demonstrate efficient bulk-wave manipulation, and help in designing compact, multichannel acoustic waveguides, and multivalley device architectures.