Impact of Topological Edge Defects on Spin Transport Properties of Zigzag Graphene Nanoribbons

Abstract

Herein, the spin‐dependent transport properties of a zigzag graphene nanoribbon (zGNR) with edges decorated with a fluoranthene group are studied. Atomically perfect zigzag edge, including phenyl‐edge functionalization, was synthesized by Ruffieux et al. in a bottom‐up chemical technique. By performing nearest‐neighbor tight‐binding model in combination with Landauer formalism and Green's function approach, as well as considering Coulomb electronic interaction computed both with density functional calculations and mean‐field approximation of the Hubbard model, the magnetic and spin‐resolved transmissions are studied. Both the model Hamiltonian and density functional theory (DFT) descriptions yield very similar results. Importantly, by generating a special supercell, three different antiferromagnetic alignments for phenyl‐edge zGNR have been calculated, which was not developed in previous studies. The results show that by adding pentagon rings on both sides of the zGNR, the conductance loses its step‐like behavior. Our structure of interest is a semiconductor with a transport gap of 0.56 eV. This kind of defective structure will enable the spin‐feature characteristic, such as spin filtering, and add the spin degree of freedom to graphene‐based logic devices.

Quasi-periodic scattering of topological edge states induced by the vacancies in chloridized gallium bismuthide nanoribbons

“…Strong backscattering may emerge depending on the edge and defect type of nanoribbons [30]. Besides, the quantum transport in nanoribbons is usually concerned with the treatment of edges [31][32][33][34][35][36][37]. More studies may be necessary to better understand the quantum transport of topological edge states in nanoribbons.…”

Effects of antidot lattices density on transport features in zigzag graphene nanoribbons

“…The electronic transport of graphene nanoribbons (GNRs) has been widely investigated during the past two decades [1][2][3][4][5][6][7][8][9] due to their potential application for designing future electronic device, such as field-effect transistors [10][11][12] and bio-sensing device [13]. Numerous previous studies have shown that the GNRs with zigzag edges (ZGNRs) exhibits metallic feature while two-thirds of armchair edged GNRs (AGNRs) are semiconducting with a small energy bandgap opening and the other one-third maintains metallic [14][15][16][17].…”

“…Therefore, much effort [18][19][20][21][22][23][24][25] has focused on the fundamental question of the bandgap engineering in GNRs because the absence of energy gap limits its application on optoelectronic devices. Chemical functionalization [3,[25][26][27] on surface or edges of GNRs can effectively modify the electronic structure and then open a transport gap. Edge roughness [18,21,28] has also been widely studied as an important way to affect the conductance of GNRs.…”