Magnetic nanographite

Abstract

Hydrogenated nanographite can display spontaneous magnetism. Recently we proposed that hydrogenation of nanographite is able to induce finite magnetization. We have performed theoretical investigation of a graphene ribbon in which each carbon is bonded to two hydrogen atoms at one edge and to a single hydrogen atom at another edge. Application of the local-spin-density approximation to the calculation of the electronic band-structure of the ribbon shows appearance of a spin-polarized flat band at the Fermi energy. Producing different numbers of mono-hydrogenated carbons and di-hydrogenated carbons can create magnetic moments in nanographite.Comment: 4 pages, 3 Postscript figures, uses revtex4.cls, submitted to Phys. Rev.

Half-Metallic Zigzag Carbon Nanotube Dots

“…This conclusion is in striking difference from the case of ZZ-GNRs, where the ground electronic state was found to have an AFM spin ordering regardless of the dimensions of the ribbon. [19][20][21][22][23][24][25][26]28,29,42,[45][46][47][48][49][50][51][52] Interestingly, contradicting results have been reported in the literature, 33 indicating that the ground state of unpassivated zigzag CNTs has a low-spin AFM ordering even for nanotubes that have earlier been considered to present a high-spin ferromagnetically ordered ground state. 32 In light of the considerable progress that has been made in the synthesis and fabrication of ultra-short [60][61][62][63][64] and open ended 65 CNTs and ultra-narrow GNRs, [66][67][68][69] it is desirable to obtain a full understanding of their electronic properties.…”

“…30,40,43 A unique mechanism for spin ordering in graphene based systems is related to the appearance of edge states. [18][19][20][21][22][23][24][25][26][27][28][29]42,[45][46][47][48][49][50][51][52] When cutting a graphene sheet along its zigzag axis to form a narrow and elongated graphene nanoribbon (GNR), distinct electronic states appear, which are localized around the exposed edges. [54][55][56][57][58][59] These states are predicted to carry spin polarization, resulting in a well defined magnetic ordering.…”

Intrinsic Magnetism of Grain Boundaries in Two-Dimensional Metal Dichalcogenides

“…First, the vanishing band gap of graphene is undesirable for switching functionalities and controllable magnetism. Second, magnetism in graphene appears to originate from vacancies [9][10][11][12], adatoms [13][14][15][16][17][18] or zigzag edges [19,20] these imperfections can be readily removed by local structural rearrangements through annealing or chemical passivation. Global topological defects such as dislocations within grain boundaries (GBs) are more robust, since they cannot be annealed away by a purely local structural rearrangement.…”

Magnetic Boron Nitride Nanoribbons with Tunable Electronic Properties

“…Albeit GNRs share many of the properties of their close relatives, carbon nanotubes (CNTs), [4][5][6] graphene nanoribbons present reactive edges that dominate their electronic and magnetic behavior. 7,8 The extreme importance of the edges in graphene has been pointed out by Wakabayashi et al 5 by considering spin-polarized theoretical models:…”