Non-equilibrium Tunneling Spectroscopy in Carbon Nanotubes

TL;DR

This paper investigates the non-equilibrium electron energy distribution in carbon nanotubes using tunneling spectroscopy, revealing weak electron interactions at low temperatures and increased relaxation rates at slightly higher temperatures.

Contribution

It provides new insights into energy relaxation processes in carbon nanotubes under non-equilibrium conditions using superconducting probe spectroscopy.

Findings

Weak electron interactions at low temperatures in nanotubes.

Energy relaxation rate increases at temperatures around 1.5 K.

Electron distribution shapes are studied under bias voltages.

Abstract

We report measurements of the non-equilibrium electron energy distribution in carbon nanotubes. Using tunneling spectroscopy via a superconducting probe, we study the shape of the local electron distribution functions, and hence energy relaxation rates, in nanotubes that have bias voltages applied between their ends. At low temperatures, electrons interact weakly in nanotubes of a few microns channel length, independent of end-to-end conductance values. Surprisingly, the energy relaxation rate can increase substantially when the temperature is raised to only 1.5 K.