Effective-mass theory of collapsed carbon nanotubes

TL;DR

This paper investigates the electronic band structure of partially flattened carbon nanotubes using an effective-mass approach, highlighting how inter-wall interactions influence their electronic properties.

Contribution

It introduces a theoretical model that accounts for inter-wall interactions in flattened nanotubes, revealing their significant impact on electronic states and phase transitions.

Findings

Inter-wall interactions are crucial in non-chiral nanotubes.

These interactions can switch nanotubes between semiconducting and metallic states.

The influence of inter-wall interactions diminishes with increasing chiral angle deviation.

Abstract

Band structure is theoretically studied in partially flattened carbon nanotubes within an effective-mass scheme. Effects of inter-wall interactions are shown to be important in non-chiral nanotubes such as zigzag and armchair and can essentially be neglected in chiral nanotubes except in the close vicinity of non-chiral tubes. In fact, inter-wall interactions significantly modify states depending on relative displacement in the flattened region in non-chiral tubes and can convert semiconducting tubes into metallic and vice versa. They diminish rapidly when the chiral angle deviates from that of the zigzag or armchair tube, although the decay is slower in the vicinity of armchair tubes.