Intrinsic half-metallicity of the Stone-Wales edge reconstructed graphene nanoribbons

Abstract

Inspired by recent experimental observation of topological line defects along graphene edges, we study the electronic and magnetic properties of the zigzag graphene nanoribbons with Stone–Wales (SW) edge reconstructions. Since the bipartite nature of graphene is broken along the boundary layer due to the SW defects, the ground state exhibits two competing phases. By increasing the onsite Coulomb interaction U above a critical value, the paramagnetic ground state makes a transition to an edge ferromagnetic phase, which is followed by a subsequent transition to an edge antiferromagnetic phase upon further increase of U. We have also demonstrated that for a zigzag graphene nanoribbon with a single SW edge reconstruction, the ground state becomes an intrinsic half‐metal for a realistic parameter range of U.

Formation of Stone–Wales edge: Multistep reconstruction and growth mechanisms of zigzag nanographene

“…Based on the discussion in step 1 and previous research about open‐edge reconstruction of carbon nanotubes, the edge reconstruction is proved as a spin reduction reaction. Moreover, an antiferromagnetic phase of GNR with a fully‐reconstructed 5–7 edge has been confirmed as the ground state in theory . Therefore, to reduce computational cost, the ground state of products with two, three, and four 5–7 pairs are set as quintet, triplet, and open‐shell singlet, respectively (Table S4‐S7 of Supporting Information).…”

“…Moreover, an antiferromagnetic phase of GNR with a fullyreconstructed 5-7 edge has been confirmed as the ground state in theory. [32] Therefore, to reduce computational cost, the ground state of products with two, three, and four 5-7 pairs are set as quintet, triplet, and open-shell singlet, respectively (Table S4-S7 of Supporting Information). As for the TS structures, optimizations are performed on two states (corresponding to the ground states of reactant and product) to choose a more stable one (Table S3 of Supporting Information).…”