Gravity Generator

Superconductivity in Ropes of
Carbon Nanotubes

Photo Courtesy Cambridge University

Los Alamos National Laboratory

By M. Ferrier, A. DeMartino, A. Kasumov,
S. Gueron, M. Kociak, R. Egger, H Bouchiat
Date: 19 May 2004

We report experimental evidence of intrinsic superconductivity below 0.5K in SWNT [single-wall nanotube] ropes, provided the distance between the electrodes is large enough. We summarize both our experimental results and the low energy theory describing the superconducting state in ropes proposed by two of us.

Attractive phonon-mediated interactions may overcome the Coulomb repulsion in a sufficiently thick rope...The dominant 1D fluctuations on individual SWNT's then cause the incipient formation of singlet Cooper pairs. Superconductivity of the ropes is finally stabilized by Cooper pair hopping between the tubes (Josephson coupling)....

The effective low-energy theory of rope superconductivity explains the experimental results on the temperature-dependent resistance below the transition temperature in terms of quantum phase slips. Quantitative agreement with only one fit parameter can be obtained. Nanotube ropes thus represent superconductors in an extreme 1D limit never before explored.

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