Itinerant Flat-Band Magnetism in Hydrogenated Carbon Nanotubes

TL;DR

This study uses ab initio calculations to explore how hydrogenation affects the electronic and magnetic properties of carbon nanotubes, revealing tunable flat-band magnetism and potential for electronic modulation.

Contribution

It demonstrates how charge transfer, structural distortion, and external stimuli can induce and control flat-band magnetism in hydrogenated carbon nanotubes.

Findings

Hydrogenation induces spin-polarized flat bands in nanotubes.

Strain and electric fields can modulate flat-band spin-splitting.

External stimuli can trigger insulator-metal transitions.

Abstract

We investigate the electronic and magnetic properties of hydrogenated carbon nanotubes using ab initio spin-polarized calculations within both the local density approximation (LDA) and the generalized gradient approximation (GGA). We find that the combination of charge transfer and carbon network distortion makes the spin-polarized flat-band appear in the tube's energy gap. Various spin-dependent ground state properties are predicted with the changes of the radii, the chiralities of the tubes and the concentration of hydrogen (H). It is found that strain or external electric field can effectively modulate the flat-band spin-splitting, and even induce an insulator-metal transition.