Direct observation of transition from Tomonaga-Luttinger liquid states to superconductive phase in carbon nanotubes

We report the direct observation of the transition from the Tomonaga-Luttinger liquid (TLL) states to the superconductive (SC) phase in partially end-bonded multi-walled carbon nanotubes, in which the SC phase and the TLL states interplay. Two different transition behaviors are observed when the temperature decreases: (1) a drastic increase in the Luttinger parameter g toward g=1 in the power laws on non-normalized differential conductance (dl/dv) vs. voltages and (2) a deviation from the TLL formula in the low voltage-energy region of normalized dl/dv vs. eV/kT. These findings shed light on understanding of one-dimensional electron correlations.