Tuning carbon nanotube bandgaps with strain

TL;DR

This study demonstrates that applying mechanical strain to carbon nanotubes can significantly modify their electronic band structure, including opening and tuning bandgaps, with experimental results aligning with theoretical predictions.

Contribution

It provides experimental validation of strain-induced bandgap tuning in carbon nanotubes, a concept previously supported mainly by theoretical models.

Findings

Strain can open a bandgap in metallic nanotubes.

Strain can modify the bandgap in semiconducting nanotubes.

Experimental results match theoretical predictions of bandgap change range.

Abstract

We show that the band structure of a carbon nanotube (NT) can be dramatically altered by mechanical strain. We employ an atomic force microscope tip to simultaneously vary the NT strain and to electrostatically gate the tube. We show that strain can open a bandgap in a metallic NT and modify the bandgap in a semiconducting NT. Theoretical work predicts that bandgap changes can range between +100meV and -100meV per 1% stretch, depending on NT chirality, and our measurements are consistent with this predicted range.