High-Tc superconductivity in entirely end-bonded multi-walled carbon nanotubes

We report that entirely end-bonded multi-walled carbon nanotubes (MWNTs) can exhibit superconductivity with a transition temperature (Tc) as high as 12 K, which is approximately 30 times greater than Tc reported for ropes of single-walled nanotubes. We find that the emergence of this superconductivity is highly sensitive to the junction structures of the Au electrode/MWNTs. This reveals that only MWNTs with optimal numbers of electrically activated shells, which are realized by end bonding, can allow superconductivity due to intershell effects.