Alteration of superconductivity and radial breathing modes in suspended ropes of carbon nanotubes by organic polymer coatings

摘要

We have altered the superconductivity of a suspended rope of single walled carbon nanotubes, by coating it with organic polymers. Upon coating, the normal state resistance of the rope changes by less than 20%. But superconductivity, which on the bare rope shows up as a substantial resistance decrease below 300 mK, is gradually suppressed. We correlate this to the suppression of radial breathing modes, measured with raman spectroscopy on suspended single and double-walled carbon nanotubes. This points to the breathing phonon modes as being responsible for superconductivity in ropes of single walled carbon nanotubes.