Abstract Submitted to the NANOTUBE'02 Workshop:

Single wall carbon nanotubes SWNT are model system for the investigation of electronic transport in one dimension. Strong indication of the presence of repulsive interactions in SWNT was given by the measurement of the power-law dependence of the conductivity at high temperature and bias voltage which extrapolates to an infinite resistance state at low temperature. These measurements, were done on nanotubes separated from measuring leads by tunnel junctions. However, because of Coulomb blockade, the low temperature and voltage regime could not be explored. In contrast, it is also possible to develop techniques in which measuring pads are connected through low contact resistance to nanotubes. When the contact pads are superconducting, nanotubes become superconducting due to proximity effect with surprising large values of supercurrent which cannot be explained by conventional theory of proximity induced superconductivity. We have also observed intrinsic superconductivity in ropes constituted from 10 to 100 single wall carbon nanotubes mounted on normal contacts. It is the essential that the distance between the normal electrodes is large enough, other wise superconductivity is destroyed by proximity effect. These experiments indicate the presence of attractive interactions in carbon nanotubes which overcome coulomb repulsive interactions at low temperature.