Gap opening in topological-defect lattices in graphene

TL;DR

This study uses ab initio calculations to explore how topological defects in graphene influence its electronic properties, revealing a variety of electronic structures including gap openings and metallic states, with implications for material design.

Contribution

It demonstrates that topological defect networks in graphene can produce diverse electronic behaviors, including gap opening, which was not previously well understood.

Findings

Defect networks produce Dirac-fermion null-gap semiconductors.

Corrugation reduces energy and density of states at Fermi level.

Gap opening occurs in some defect configurations.

Abstract

Ab initio calculations indicate that topological-defect networks in graphene display the full variety of single-particle electronic structures, including Dirac-fermion null-gap semiconductors, as well as metallic and semiconducting systems of very low formation energies with respect to a pristine graphene sheet. Corrugation induced by the topological defects further reduces the energy and tends to reduce the density of states at the Fermi level, to widen the gaps, or even to lead to gap opening in some cases where the parent planar geometry is metallic.