Strain induced correlation gaps in carbon nanotubes

TL;DR

This paper predicts that uniaxial strain in armchair carbon nanotubes increases the correlation gap significantly, contrasting with band theory predictions, using a Hartree-Fock Hubbard model approach.

Contribution

It introduces a method to calculate strain-induced correlation gap changes in carbon nanotubes considering electron correlations.

Findings

Correlation gap enlarges with strain by several meV per percent.

Pure band structure calculations predict no change in correlation gap for armchair nanotubes.

Correlation effects are modeled using a self-consistent Hartree-Fock approximation.

Abstract

We calculate the change in the correlation gap of armchair carbon nanotubes with uniaxial elastic strain. We predict that such a stretching will enlarge the correlation gap for all carbon nanotubes by a change that could be as large as several meV per percent of applied strain, in contrast with pure band structure calculations where no change for armchair carbon nanotubes is predicted. The correlation effects are considered within a self-consistent Hartree-Fock approximation to the Hubbard model with on-site repulsion only.