Control of terahertz elastic wave bandgaps in multilayered van der Waals metamaterials

Abstract

Multilayered van der Waals (vdW) devices have demonstrated exceptional terahertz (THz) phonon manipulation capabilities, which can be dynamically tailored through twist angle adjustments and strain modulation. However, their vibration suppression capability remains largely unexplored. The bandgap characteristics of elastic waves in multilayered vdW metamaterials with fixed boundaries are investigated by the molecular dynamics method. The results demonstrate that both the frequency and width of the broad THz bandgap in vdW metamaterials can be dynamically controlled by varying in-plane dimensions, twist angles, and in-plane strains. Alterations in twist angles and small strains have negligible effects on low-frequency transmissibility but can significantly modulate both the width and frequency of high-frequency bandgaps. Furthermore, bandgap splitting phenomena are observed under biaxial strain due to changes in resonance modes. This work offers insights into vibration isolation and phonon engineering in vdW heterostructure-based devices.