a tddft investigation on plasmons in multilayer graphene nanostructures

Using time-dependent density function theory (tddft), we have carried out a systematic study of collective excitations of the ab-stacked and aa-stacked few-layer graphene nanostructures with rectangle geometries. we found little effect of stacking sequence on the excitation properties of few-layer graphene nanostructures when the polarized direction of impulse excitation is in the armchair-edge or in the zigzag-edge directions. however, the effect of the stacking sequence becomes significant when the polarized direction was perpendicular to the layers. the absorption strength in the bilayer/trilayer system is slightly more than twice/three times as strong as that in the monolayer system. with the increase of the number of the layers, in the lower-energy resonance zone, absorption spectra are blue-shifted. the increasing strength of the optical absorption has also been found when the interlayer distance is increased followed by red shift in the supreme absorption peak. we found high energy resonances of πplasmons at 4–8 ev are localized in the boundary region showing dipole-like character. the current findings pave a way for the potential applications in uv regions if there are available nanomechanical devices to tune stacking and interlayer distance.