van der Waals interaction in magnetic bilayer graphene nanoribbons

Abstract

We study the interaction energy between two graphene nanoribbons by first-principles calculations, including van der Waals interactions and spin polarization. For ultranarrow zigzag nanoribbons, the direct stacking is even more stable than the Bernal stacking, competing in energy for wider ribbons. This behavior is due to the magnetic interaction between edge states. We relate the reduction of the magnetization in zigzag nanoribbons with increasing ribbon width to the structural changes produced by the magnetic interaction, and we show that when deposited on a substrate, zigzag bilayer ribbons remain magnetic for larger widths.

A tunable electronic beam splitter realized with crossed graphene nanoribbons

“…All calculations were therefore performed using the vdW density functional of Dion et al 62 with the modified exchange by Klimeš, Bowler and Michaelides 63 since the description of dispersive interactions is crucial to describe interlayer binding and density rearrangment. 64 The core electrons were described by non-local Troullier-Martins pseudopotentials 65 and a double-ζ basis set was used to expand the valence-electron wavefunctions. 57 The fineness of the real space grid and the orbital radii were defined using, respectively, a 350 Ry energy cutoff and a 30 meV energy shift.…”

Topologically confined states at corrugations of gated bilayer graphene

“…These ripples can lead to interesting electronic [38][39][40], magnetic [41], and chemical properties [42], mostly due to the associated charge inhomogeneity and the changes in hybridization. In fact, folding graphene has been put forward as a way to modify its properties [43][44][45]; also, folded ribbons have been proposed as graphene-based electronic connectors between edges or graphene layers [46].…”

Edge-state magnetism in hydrogenated armchair carbon nanotubes

“…respectively, each corresponding to the BE and ZE parts. In the AFM states, the spin configuration between the two parts is the same as the intralayer antiferromagnetic and interlayer ferromagnetic spin configuration in bilayer ZGNRs [20]. When N 3, the edgelocalized states are formed only in the ZE part but not in the BE part as shown in Fig.…”