Electronic Density of States of Atomically Resolved Single-Walled Carbon Nanotubes: Van Hove Singularities and End States

TL;DR

This study uses scanning tunneling microscopy to analyze the electronic density of states in single-walled carbon nanotubes, revealing Van Hove singularities and end states, with experimental results supported by tight-binding calculations.

Contribution

It provides atomically resolved measurements of the density of states in nanotubes and links observed features to atomic arrangements at the tube ends.

Findings

Identification of Van Hove singularities in the density of states.

Observation of new low-energy peaks near nanotube ends.

Correlation of spectral features with atomic structure at tube termini.

Abstract

The electronic density of states of atomically resolved single-walled carbon nanotubes have been investigated using scanning tunneling microscopy. Peaks in the density of states due to the one-dimensional nanotube band structure have been characterized and compared with the results of tight-binding calculations. In addition, tunneling spectroscopy measurements recorded along the axis of an atomically-resolved nanotube exhibit new, low-energy peaks in the density of states near the tube end. Calculations suggest that these features arise from the specific arrangement of carbon atoms that close the nanotube end.