Pseudo-spin-dependent scattering in carbon nanotubes

TL;DR

This paper explores how defect-induced symmetry breaking affects electron scattering in carbon nanotubes, revealing pseudo-spin conservation rules and proposing defect engineering for device applications.

Contribution

It provides a detailed analysis of pseudo-spin-dependent scattering due to defects in carbon nanotubes, linking symmetry breaking to experimental observations and device design.

Findings

Pseudo-spin conservation depends on defect-induced symmetry breaking.

Lack of particle-hole symmetry influences scattering channels.

Defect engineering can be used to design pseudo-spin filters.

Abstract

The breaking of symmetry is the ground on which many physical phenomena are explained. This is important in particular for bipartite lattice structure as graphene and carbon nanotubes, where particle-hole and pseudo-spin are relevant symmetries. Here we investigate the role played by the defect-induced breaking of these symmetries in the electronic scattering properties of armchair single-walled carbon nanotubes. From Fourier transform of the local density of states we show that the active electron scattering channels depend on the conservation of the pseudo-spin. Further, we show that the lack of particle-hole symmetry is responsible for the pseudo-spin selection rules observed in several experiments. This symmetry breaking arises from the lattice reconstruction appearing at defect sites. Our analysis gives an intuitive way to understand the scattering properties of carbon nanotubes, and can be employed for newly interpret several experiments on this subject. Further, it can be used to design devices such as pseudo-spin filter by opportune defect engineering.