Ferromagnetic Ordering in Carbon Nanotubes, Incorporated in Diamond Single Crystals

TL;DR

This paper investigates the origin of ferromagnetic ordering in carbon nanotubes created within diamond crystals, attributing it to the asymmetry in the spin density of a specific electronic subsystem, and discusses coexistence with superconductivity.

Contribution

It reveals that the ferromagnetism in ion beam modified carbon nanotubes is due to the π-electronic subsystem's asymmetry, modeled by a generalized SSH framework, and reports coexistence with superconductivity at room temperature.

Findings

Ferromagnetism is linked to the π-electronic subsystem's asymmetry.

Formation of SSH topological soliton lattice explains the ferromagnetic behavior.

Uncompensated antiferromagnetic ordering coexists with superconductivity at room temperature.

Abstract

The physical origin of the mechanism of the formation of ferromagnetic ordering in carbon nanotubes (NTs), produced by high energy ion beam modification of diamond single crystals in $\langle{110}\rangle$ and $\langle{111}\rangle$ directions has been found. It is concluded from analysis of experimental results on ferromagnetic spin wave resonance observed, that the only $\pi$-electronic subsystem of given NTs is responsible for the appearance of ferromagnetism. It is determined by asymmetry in spin density distribution in Su-Schrieffer-Heeger (SSH) topological soliton lattice. The formation of SSH topological soliton lattice is considered in the frames of generalized SSH-model of organic conductors, in which $\pi$-electronic subsystem is represented being to be 1D quantum Fermi liquid. The phenomenon of formation of uncompensated antiferromagnetic ordering coexisting with superconductivity at room temperature in carbon nanotubes, produced by high energy ion beam modification of diamond single crystals in $\langle{100}\rangle$ direction is argued.