Abstract Submitted to the    NANOTUBE'06 Conference:

Current Induced Reversible Deformation of Carbon Nanotubes

Yoshikazu Nakayama

Osaka Prefecture University, Osaka University

nakayama@pe.osakafu-u.ac.jp

XII. Thermal and Mechanical Properties of Nanotubes

We induced a permanent plastic deformation in an originally straight double-walled carbon nanotube by applying current to an individual nanotube that had been bent elastically under mechanical duress. The onset of plastic deformation, as measured using the current circumference-density, is less than 1/20 that causing sublimation. Applying a large current to the permanent bend in the nanotube recovered the original straight shape. Its onset circumference-density is close to that of sublimation. The plastic bending deformation and its recovery can be performed cyclically, indicating that the deformed structure is metastable.

The minimum energy path calculation with a bond-order potential well explained the experimental results and suggests the following model. The moderate energetic perturbation under the strain induces bond switching to form Stone-Wales defects, and the pentagons and heptagons in the defects move to minimize the total energy. Thereby, the plastic deformation of the permanent bend is completed, because the adequate substitution of pentagons and heptagons for hexagons permanently bends the tubes. When the high energy is given to raise the temperature up to that of sublimation, the bond switching occurs to recover the bend.

Our findings will allow developing the nanotube static devices and actuator devices with high performances.

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