Spatial Dependence of Electron Interactions in Carbon Nanotubes

TL;DR

This paper investigates how electron interactions vary spatially within carbon nanotubes, revealing that transport is mainly diffusive due to elastic scattering, but local inelastic scattering can be controlled via gate voltage.

Contribution

It introduces a method using multiple superconducting probes to measure spatial electron energy distributions and characterizes the nature of electron transport and interactions in nanotubes.

Findings

Transport is predominantly diffusive due to elastic scattering from defects.

Local inelastic scattering can be toggled with gate voltage.

Electron interactions are spatially dependent and tunable.

Abstract

We report measurements of the spatial dependence of the electron energy distribution in carbon nanotubes, from which electron interactions are determined. Using nonequilibrium tunneling spectroscopy with multiple superconducting probes, we characterize electron transport as ballistic or diffusive, and interactions as elastic or inelastic. We find that transport in nanotubes is generally diffusive, caused by elastic scattering from a few defects. However, local inelastic scattering can be tuned `on' or `off' with a gate voltage.