Molecular Dynamics Study on Buckling Behavior of Non-Defective and Defective Triple-Walled Carbon Nanotubes

概要

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In order to discuss the origin of the buckling of carbon nanotubes from the atomic level, we have performed the compressive simulation of non-defective and defective triple-walled carbon nanotubes (TWCNT) by the molecular dynamics method using the adaptive intermolecular reactive empirical bond order potential, and observed changes in atomic stresses until the buckling. In the non-defective TWCNT, standard deviations of atomic axial stresses rise drastically before the buckling. The transition from homogeneous stress distributions to inhomogeneous ones play an important role in the occurrence of the buckling. In TWCNTs with a vacancy-type defect or a Stone-Wales defect, buckling stresses differ according to location of the defect. Repulsive interlayer interactions caused by the constriction of the outer layer including a defect reduce significantly the buckling strength. On the other hand, constrictions of the middle or inner layer including a defect produce slightly attractive interaction with the outer layer. Therefore, whole layers is buckled at the same time as the buckling of the outer non-defective layers. TWCNTs including many defects that are generated by the heat treatment simulation show smaller buckling stresses than that of TWCNTs including a defect. Defect configurations have a significant influence on distribution of atomic stresses until the buckling. The buckling occurs from constriction parts located close to defects.