Stochastic stress jumps due to soliton dynamics in two-dimensional van der Waals interfaces

The creation and movement of dislocations determine the nonlinear mechanics of materials. At the nanoscale, the number of dislocations in structures become countable, and even single defects impact material properties. While the impact of solitons on electronic properties is well studied, the impact of solitons on mechanics is less understood. In this study, we construct nanoelectromechanical drumhead resonators from Bernal stacked bilayer graphene and observe stochastic jumps in frequency. Similar frequency jumps occur in few-layer, but not twisted-bilayer or monolayer graphene. Using atomistic simulations, we show that the measured shifts are a result of changes in stress due to the creation and annihilation of individual solitons. We develop a simple model relating the magnitude of the stress induced by soliton dynamics across length scales, ranging from < 0.01 N/m for the measured 5 μm diameter to ~ 1.2 N/m for the 38.7 nm simulations. These results demonstrate the sensitivity of 2D resonators are suf...