Metal-to-semiconductor transition in squashed armchair carbon nanotubes

TL;DR

This paper studies how squashing armchair carbon nanotubes induces a transition from metallic to semiconducting behavior, revealing the underlying mechanism involving symmetry breaking and bond formation.

Contribution

It provides a detailed analysis of the metal-to-semiconductor transition mechanism in squashed nanotubes, combining molecular dynamics and Green's function methods.

Findings

Squashing induces a metal-to-semiconductor transition.

Breaking mirror symmetry and bond formation are essential for the transition.

An energy gap near the Fermi level is opened by the transition.

Abstract

We investigate electronic transport properties of the squashed armchair carbon nanotubes, using tight-binding molecular dynamics and Green's function method. We demonstrate a metal-to-semiconductor transistion while squashing the nanotubes and a general mechanism for such transistion. It is the distinction of the two sublattices in the nanotube that opens an energy gap near the Fermi energy. We show that the transition has to be achieved by a combined effect of breaking of mirror symmetry and bond formation between the flattened faces in the squashed nanotubes.