Local pressure-induced metallization of a semiconducting carbon nanotube in a crossed junction

TL;DR

This study demonstrates that local pressure at a crossed junction can induce metallization in a semiconducting carbon nanotube, with electronic and vibrational changes confirmed by advanced spectroscopy techniques.

Contribution

It provides direct experimental evidence of pressure-induced local metallization in a semiconducting nanotube and highlights the role of mechanical deformation and image charges.

Findings

Radial compression causes local metallization of the nanotube.

Vibrational modes are highly sensitive to local mechanical deformation.

Image charges significantly influence contact potential at interfaces.

Abstract

The electronic and vibrational density of states of a semiconducting carbon nanotube in a crossed junction was investigated by elastic and inelastic scanning tunneling spectroscopy. The strong radial compression of the nanotube at the junction induces local metallization spatially confined to a few nm. The local electronic modifications are correlated with the observed changes in the radial breathing and G-band phonon modes, which react very sensitively to local mechanical deformation. In addition, the experiments reveal the crucial contribution of the image charges to the contact potential at nanotube-metal interfaces.