Many body effects in finite metallic carbon nanotubes

TL;DR

This paper investigates how charge distribution non-homogeneity in metallic carbon nanotubes causes excitonic resonances, affecting tunneling density of states and electron interactions, with implications for device coupling.

Contribution

It introduces the role of charge non-homogeneity and excitonic effects in tunneling properties of metallic nanotubes, highlighting the influence of metallic gates on electron interactions.

Findings

Positive low-bias anomaly in tunneling density of states

Screening effects modify electron-electron interactions

Charge non-homogeneity induces excitonic resonances

Abstract

The non homogeneity of the charge distribution in a carbon nanotube leads to the formation of an excitonic resonance, in a similar way to the one observed in X-ray absorption in metals. As a result, a positive anomaly at low bias appears in the tunnelling density of states. This effect depends on the screening of the electron--electron interactions by metallic gates, and it modifies the coupling of the nanotube to normal and superconducting electrodes.