The low energy spectrum of finite size metallic SWNTs

TL;DR

This paper derives the low-energy electronic spectrum of finite-size metallic single-wall carbon nanotubes, considering both Coulomb interactions and lattice substructure effects, revealing ground state spin configurations and excitation spectra.

Contribution

It provides a comprehensive derivation of the low-energy spectrum including all relevant interactions and lattice effects, extending previous models that only considered forward scattering.

Findings

Ground state can be a spin 1 triplet or spin 0 singlet depending on exchange splitting and branch mismatch.

Excitation spectrum characterized for finite-size metallic SWNTs.

All relevant interaction processes are included in the analysis.

Abstract

The electronic spectrum of metallic finite-size single-wall carbon nanotubes at low energies is derived. It is based on a tight-binding description for the interacting p_{z} electrons. Not only the forward scattering parts of the Coulomb interaction, which are diagonalized by bosonization, are considered, but also all other processes becoming relevant for small diameter tubes. As a consequence of the substructure of the underlying lattice, a spin 1 triplet is found as ground state if the exchange splitting is larger than the branch mismatch, a spin 0 singlet otherwise. Moreover the excitation spectrum is calculated.