▎ 摘　　要

In crystalline materials, the creation and modulation of dislocations are often associated with plastic deformation and energy dissipation. Here, we report a study on the energy dissipation of a trilayer graphene ribbon resonator. The vibration of the ribbon generates cyclic mechanical loading to the graphene ribbon during which mechanical energy is dissipated as heat. Measuring the quality factor of the graphene resonator provides a method to evaluate the energy dissipation. The graphene ribbon is integrated with silicon microactuators, allowing its in-plane tension to be finely tuned. As we gradually increased the tension, we observed, in addition to the well-known resonance frequency increase, a large change in the energy dissipation. We propose that the dominating energy dissipation mechanism shifts over three regions. With small applied tension, the graphene is in the elastic region, and the major energy dissipation is through graphene edge folding; as the tension increases, dislocations start to develop in the sample to gradually dominate the energy dissipation; finally, at large enough tension, graphene layers become decoupled and start to slide and cause friction, which induces more severe energy dissipation. The generation and modulation of dislocations are modeled by the molecular dynamics calculation and a method to count the energy loss is proposed and compared with the experiment.