Energy transfer in strained graphene assisted by discrete breathers excited by external ac driving

TL;DR

This study uses molecular dynamics to show how external ac driving can excite discrete breathers in strained graphene nanoribbons, enabling energy transfer even at low amplitudes, with implications for controlling energy flow.

Contribution

It demonstrates that external harmonic driving outside the phonon spectrum can effectively excite discrete breathers in strained graphene, facilitating energy transfer at small amplitudes.

Findings

Discrete breathers can be excited by external ac driving in strained graphene.

Energy transfer is possible with relatively small driving amplitudes.

Differences between displacement and force driving modes are analyzed.

Abstract

In the present molecular dynamics study, external ac driving is used at frequencies outside the phonon spectrum to excite gap DBs in uniformly strained graphene nanoribbon. Harmonic displacement or harmonic force is applied to a zigzag atomic chain of graphene. In the former case non-propagating DBs are excited on the atoms next to the driven atoms, while in the latter case the excited DBs propagate along the nanoribbon. The energy transfer along the nanoribbon assisted by the DBs is investigated in detail and the differences between harmonic displacement driving and harmonic force driving are discussed. It is concluded that the amplitude of external driving at out of phonon spectrum frequencies should not necessarily be large to obtain a noticeable energy transfer to the system. Overall, our results suggest that external harmonic driving even at relatively small driving amplitudes can be used to control excitation of DBs and consequently the energy transfer to the system.