Magneto-mechanical–thermal coupling regulation of Weyl surface state topological transport in three-dimensional magnetoelastic phononic crystals

Abstract

Weyl phononic crystals (PCs), as a key platform for topological states, feature doubly degenerate Weyl points of band structures in three-dimensional (3D) space. Their investigation has expanded from electronic systems to classical waves, including electromagnetic, acoustic, and elastic waves, and has drawn extensive attention. However, elastic wave systems are limited by fixed structures, making the active modulation of topological surface states challenging. To overcome these limitations, we design a tunable 3D Weyl magnetoelastic PC composed of magnetostrictive materials integrated with an elastic substrate. Based on the magneto-mechanical–thermal coupled constitutive relation of magnetostrictive materials, we have achieved the spatial inversion symmetry breaking under the collaborative regulation of magnetic and thermal fields, and observed the elastic wave Weyl points and their frequency-tunable characteristics. We further examine the robust transport of Weyl surface states under waveguide and defect conditions, as well as layer-selective transmission achieved through boundary condition design. This work provides a new route for dynamic regulation of elastic wave topological transport and offers significant potential for the development of customizable topological devices.