Phase-coherent transport in ropes of single-wall carbon nanotubes

To study the phase breaking scattering events in single-wall carbon nanotubes (SWNTs), ropes of SWNTs are intentionally damaged by ${\mathrm{Ar}}^{+}$ ion milling. Due to this treatment, the average distance an electron can travel before being elastically scattered is reduced to about 10 nm. This significantly increases the probability of one-dimensional localization and allows us to obtain the phase coherence length ${(L}_{\Phi })$ in ropes of SWNTs as a function of temperature. We find that Nyquist scattering $\left({\tau }_{\Phi }\sim T^{-2/3}\right)$ as well as another dephasing mechanism with a ${\tau }_{\Phi }\sim T^{-1}$ dependence are involved in limiting the phase-coherent transport. We also investigate the scattering of hot electrons in the system. The results support the statement that two different scattering mechanisms dominate the phase coherence length for different rope samples.