Dislocation induced energy dissipation in a tunable trilayer graphene resonator

TL;DR

This study investigates how dislocations in a tunable trilayer graphene resonator influence energy dissipation, revealing a transition from edge folding to dislocation activity and layer sliding as tension increases.

Contribution

It introduces a detailed analysis of dislocation-related energy dissipation mechanisms in graphene resonators with experimental and molecular dynamics modeling.

Findings

Energy dissipation varies with applied tension.

Dislocation activity becomes dominant at intermediate tension.

Layer sliding causes severe dissipation at high tension.

Abstract

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 way to evaluate the energy dissipation. The graphene ribbon is integrated with silicon micro actuators, 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 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 the more severe energy dissipation. The generation and modulation of dislocations are modeled by molecular dynamics calculation and a method to count the energy loss is proposed and compared to the experiment.