Superconductivity in 4 angstrom single-walled carbon nanotubes

Investigation of the magnetic and transport properties of single-walled sma ll-diameter carbon nanotubes embedded in a zeolite matrix revealed that at temperatures below 20 kelvin, 4 angstrom tubes exhibit superconducting beha vior manifest as an anisotropic Meissner effect, with a superconducting gap and fluctuation supercurrent. The measured superconducting characteristics display smooth temperature variations owing to one-dimensional fluctuation s, with a mean-field superconducting transition temperature of 15 kelvin. S tatistical mechanic calculations based on the Ginzburg-Landau free-energy f unctional yield predictions that are in excellent agreement with the experi ments.