The Importance of Edge Effects on the Intrinsic Loss Mechanisms of Graphene Nanoresonators

TL;DR

This study uses molecular dynamics simulations to identify edge-induced vibrational modes as the main intrinsic loss mechanism in graphene nanoresonators, and explores methods to mitigate these effects to improve Q-factors.

Contribution

It reveals that fixing free edges reduces edge modes, hydrogen passivation is ineffective, and tensile strain enhances Q-factors across temperatures.

Findings

Edge modes dominate intrinsic losses in graphene nanoresonators.

Fixing free edges significantly reduces spurious vibrational states.

Applying tensile strain improves Q-factors at various temperatures.

Abstract

We utilize classical molecular dynamics simulations to investigate the intrinsic loss mechanisms of monolayer graphene nanoresonators undergoing flexural oscillations. We find that spurious edge modes of vibration, which arise not due to externally applied stresses but intrinsically due to the different vibrational properties of edge atoms, are the dominant intrinsic loss mechanism that reduces the Q-factors. We additionally find that while hydrogen passivation of the free edges is ineffective in reducing the spurious edge modes, fixing the free edges is critical to removing the spurious edge-induced vibrational states. Our atomistic simulations also show that the Q-factor degrades inversely proportional to temperature; furthermore, we also demonstrate that the intrinsic losses can be reduced significantly across a range of operating temperatures through the application of tensile mechanical strain.