Observation of peak splitting in the Coulomb blockade regime of a carbon nanotube rope

Electronic transport measurements have been carried out on a single-walled carbon nanotube (SWCN) rope contacted to a 4-probe Au/Pd electrode in the Coulomb blockade regime. With varying substrate backgate voltage, the observed Coulomb blockade peaks exhibit interesting three-way splitting. We find that this peak splitting can be attributed to a contribution from resonant tunnelling through discrete energy levels of a finite length metallic SWCN within the rope. We also consider the role that interactions between `quantum dotʹ (Q-dot) regions within the rope can play in causing the peak splitting.