Tunable elastic wave bandgaps by strain engineering of multilayered van der Waals metamaterials

Multilayered van der Waals (vdW) metamaterials exhibit exceptional mechanical and thermal properties, with the ability to tune these characteristics based on material composition, stacking sequences, and the number of layers. Due to the extremely small scale of these structures, the influence of vibration and noise becomes significant. This study uses molecular dynamics (MD) simulations to investigate the bandgap characteristics of elastic waves in multilayered h-BN/MoS₂ vdW metamaterials. It demonstrates that the position and width of the broadband terahertz elastic wave bandgap in these materials can be adjusted by modifying the longitudinal strain and stacking order. The bandgap is notably sensitive to the rate of longitudinal strain, with its frequency increasing under compressive strain and decreasing under tensile strain. The effects of tensile and compressive strains on the bandgap are asymmetric; compressive strain can notably alter the bandgap width and even cause it to disappear. Additionally, the bandgap can be manipulated by shifting the position of the h-BN atomic layer or by rotating the h-BN layer by 90° within the metamaterial's unit cell. This research offers a novel method for tuning elastic wave propagation in multilayered vdW heterostructures.