Effect of grain boundaries on mechanical transverse wave propagations in graphene

Abstract: The effects of grain boundary (GB) on the mechanical transverse wave propagation in graphene are studied via molecular dynamics simulations and frequency spectrum analysis. We reveal that GB can attenuate transverse waves at terahertz frequencies in graphene, which might be significant for manipulating terahertz noises via nanostructured modifications in graphene-based nanodevices. Two fundamental mechanisms, scattering and resonance, are found in the attenuation of terahertz waves. The scattering impairs waves slightly with a wide range of effective frequencies, whereas the resonance, occurring in the vicinity of GB, significantly reduces the amplitude responses near resonance frequencies, which displays a special frequency-selective filter-like behavior. Moreover, the strong correlation between amplitude loss and buckling height further demonstrates the effects of GB on terahertz mechanical waves in graphene with different chiralities and misorientation angles.