Structural and electronic properties of the metal-metal intramolecular junctions of single-walled carbon nanotubes

TL;DR

This study investigates the atomic and electronic structures of metal-metal intramolecular junctions in single-walled carbon nanotubes, revealing how defect configurations influence electronic properties and proposing a model consistent with experimental observations.

Contribution

It combines DFT and force field methods to optimize IMJ structures and analyzes the effects of topological defects on electronic properties, introducing a new IMJ model.

Findings

Topological defects significantly affect local density of states.

Sigma-pi coupling is negligible near Fermi energy.

Proposed IMJ model aligns with experimental data.

Abstract

Several intramolecular junctions (IMJs) connecting two metallic (11, 8) and (9, 6) carbon nanotubes along their common axis have been realized by using a layer-divided technique to the nanotubes and introducing the topological defects. Atomic structure of each IMJ configuration is optimized with a combination of density-functional theory (DFT) and the universal force field (UFF) method, based upon which a four-orbital tight-binding calculation is made on its electronic properties. Different topological defect structures and their distributions on the IMJ interfaces have been found, showing decisive effects on the localized density of states, while the sigma-pi coupling effect is negligible near Fermi energy (EF). Finally, a new IMJ model has been proposed, which probably reflects a real atomic structure of the M-M IMJ observed in the experiment [Science 291, 97 (2001)].