Crystalline Ropes of Metallic Carbon Nanotubes
Fullerene single-wall nanotubes (SWNTs) were produced in yields of more than 70 percent by condensation of a laser-vaporized carbon-nickel-cobalt mixture at 1200degreesC. X-ray diffraction and electron microscopy showed that these SWNTs are nearly uniform in diameter and that they self-organize into "ropes," which consist of 100 to 500 SWNTs in a two-dimensional triangular lattice with a lattice constant of 17 angstroms. The x-ray form factor is consistent with that of uniformly charged cylinders 13.8 +/- 0.2 angstroms in diameter. The ropes were metallic, with a single-rope resistivity of <10(-4) ohm-centimeters at 300 kelvin. The uniformity of SWNT diameter is attributed to the efficient annealing of an initial fullerene tubelet kept open by a few metal atoms; the optimum diameter is determined by competition between the strain energy of curvature of the graphene sheet and the dangling-bond energy of the open edge, where growth occurs. These factors strongly favor the metallic (10,10) tube with C5v symmetry and an open edge stabilized by triple bonds.
Thess
A
A. Thess, P. Nikolaev, H. Dai, C. Xu, A. G. Rinzler, D. T. Colbert, G. E. Scuseria, R. E. Smalley, Center for Nanoscale Science and Technology, Rice Quantum Institute, and Departments of Chemistry and Physics, Mail Stop 100, Rice University, Post Office Box 1892, Houston, TX 77251, USA. R. Lee and J. E. Fischer, Department of Materials Science and Engineering and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104-6272, USA. P. Petit and J. Robert, Institut Charles Sadron, 6 rue Boussingault, 67000 Strasbourg, France. Y. H. Lee, S. G. Kim, D. Tomanek, Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824-1116, USA.
Lee
R
Nikolaev
P
Dai
H
Petit
P
Robert
J
Xu
C
Lee
YH
Kim
SG
Rinzler
AG
Colbert
DT
Scuseria
GE
Tomanek
D
Fischer
JE
Smalley
RE