Metamaterial-like vibration of doublewalled carbon nanotubes

Abstract

Inspirited by the similarity between counter-phase intertube vibration of multiwalled carbon nanotubes and counter-phase internal vibration of locally resonant metamaterials, forced vibration of DWCNTs (doublewalled carbon nanotubes) as a metaelastic material is investigated. It is found that unlike known elastic metamaterials characterized by wavelength-independent effective mass, “effective mass” of a DWCNT depends on wavelength and its “bandgap” (within which effective mass is negative) varies with wavelengths. For the first time in existing literature, our results confirmed that when the applied exciting frequency approaches or exceeds the lowest intertube resonant frequency, the amplitude of forced vibration of a DWCNT is more than one order of magnitude smaller than those driven by the force of same magnitude with an exciting frequency much lower than the lowest intertube resonant frequency. This result suggests that the counter-phase intertube vibration stimulated at terahertz frequencies has a remarkable effect to suppress forced vibration of DWCNTs, and DWCNTs exhibit metamaterial-like vibration behavior in the terahertz range. Similar conclusion is expected for MWCNTs (multiwalled carbon nanotubes) and may provide useful insights into vibration controlling of MWCNTs at terahertz frequencies.