Synthetic gauge field enabled realization of bulk- and edge-transported states in an aperiodic acoustic structure

TL;DR

This paper demonstrates how synthetic gauge fields in an aperiodic acoustic structure can produce topologically protected bulk and edge states, enabling robust and controllable acoustic transport with potential for advanced device applications.

Contribution

It introduces the use of synthetic gauge fields to realize and control topological acoustic states, including Landau levels and rainbow states, in an aperiodic structure, advancing topological acoustics.

Findings

Landau levels achieved in aperiodic acoustic structures under pseudomagnetic fields

Zero order Landau modes can transmit as bulk or edge states

Formation of Landau rainbow states with combined pseudomagnetic and pseudoelectric fields

Abstract

Topologically protected edge states with immunity against various disorders have been implemented in a variety of topological insulators. In this Letter, we reveal that Landau levels in aperiodic acoustic structures can be achieved under different pseudomagnetic fields (PMFs). The produced zero order Landau modes (ZOLMs) could transmit along the channels at the interior or exterior of the inhomogeneous array, which are separately termed as "bulk-transported states" (BTSs) and "edge-transported states" (ETSs). Distinct from conventional valley edge states, the ZOLMs show intriguing self-collimation feature. If a pseudoelectric field (PEF) is further included, the combination of a PMF and PEF can result in the formation of bulk or edge Landau rainbow, where Landau zero modes are distributed at various positions of the bulk or boundary of the sample at different frequencies. The synthetic-gauge-field-controlled topological states can enable fully control of robust transmission, and using the entire footprint of a topological lattice. Our findings not only profoundly advance the current understanding of topological phase matter but also offer new avenues for constructing topological acoustic devices.