Half-metallic Dirac cone in zigzag-graphene-nanoribbon/graphene

TL;DR

This paper demonstrates that zigzag graphene nanoribbons supported on graphene can exhibit half-metallic Dirac cones due to spin and pseudospin symmetry breaking, opening new avenues for graphene nanoelectronics.

Contribution

It reveals that supported zigzag graphene nanoribbons become half-metallic with Dirac cones, a novel electronic property induced by symmetry breaking.

Findings

Half-metallic Dirac cones are formed near the Fermi level.

Supported zigzag nanoribbons exhibit spin- and pseudospin-symmetry breaking.

Potential for manipulating graphene's electronic properties in nanoelectronics.

Abstract

The Dirac electrons of graphene, an intrinsic zero gap semiconductor, uniquely carry spin and pseudospin that give rise to many fascinating electronic and transport properties. While isolated zigzag graphene nanoribbons are antiferromagnetic semiconductors, we show by means of first-principles and tight-binding calculations that zigzag graphene nanoribbons supported on graphene are half-metallic as a result of spin- and pseudospin-symmetry breaking. In particular, half-metallic Dirac cones are formed at K (K') near the Fermi level. The present results demonstrate that the unique combination of spin and pseudospin in zigzag graphene nanoribbons may be used to manipulate the electronic properties of graphene, and may have practical implications for potential graphene-based nanoelectronic applications.