Meron Spin Textures Mediated by Acoustic Phase Singularities

TL;DR

This paper introduces a new framework for stationary topological acoustic spin textures based on acoustic spin, demonstrating stable meron lattices supported by spoof surface acoustic-wave modes and highlighting their robustness and controllability.

Contribution

The authors propose and experimentally demonstrate a novel approach to creating stationary topological acoustic spin textures using acoustic spin and phase singularities.

Findings

Stable acoustic spin meron lattices supported by spoof surface acoustic-wave modes.

Phase singularities in standing waves are crucial for acoustic spin formation.

Topological spin textures are robust against boundary scattering and defects.

Abstract

Existing acoustic topological textures are predominantly constructed within velocity fields, where the corresponding physical observables typically exhibit harmonic temporal oscillations. In contrast, stationary topological acoustic textures are highly desirable for characterizing topological phenomena and advancing potential applications of topological quasiparticles. Here, we propose a novel framework for topological acoustic spin textures rooted in acoustic spin, and experimentally demonstrate stable acoustic spin meron lattices supported by spoof surface acoustic-wave modes. We show that phase singularities in acoustic standing waves play a pivotal role in the formation of acoustic spin. Furthermore, we demonstrate that the phase differences among distinct groups of standing waves govern the polarization of the emergent topological quasiparticles and enable precise modulation of their intensities. Moreover, the resulting topological spin textures exhibit remarkable robustness against boundary scattering and local structural defects. Our findings establish acoustic spin as a fundamental degree of freedom for engineering topological quasiparticles in acoustics and open a new avenue toward programmable stationary topological acoustic textures.