Spin-Dependence in Asymmetric, V-Shaped-Notched Graphene Nanoribbons

Hancock, Yvette; Saloriutta, Karri; Uppstu, Andreas; Harju, Ari; Puska, Martti J.

doi:10.1007/s10909-008-9838-y

Cited by 20 publications

(20 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Magnetization has also been studied in carved slits, 23 finite ribbons 24 and flakes 24,25 as well as rings 29 and notches. 30 Recently, DFT treatments of magnetic properties of nanoholes in graphene 31 and graphene films 32 have been published.…”

Section: Introductionmentioning

confidence: 99%

Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin

et al. 2009

View full text Add to dashboard Cite

Graphene sheets with regular perforations, dubbed as antidot lattices, have theoretically been predicted to have a number of interesting properties. Their recent experimental realization with lattice constants below 100 nanometers stresses the urgency of a thorough understanding of their electronic properties. In this work, we perform calculations of the band structure for various hydrogen-passivated hole geometries using both spinpolarized density functional theory ͑DFT͒ and DFT based tight-binding ͑DFTB͒ and address the importance of relaxation of the structures using either method or a combination thereof. We find from DFT that all structures investigated have band gaps ranging from 0.2 to 1.5 eV. Band gap sizes and general trends are well captured by DFTB with band gaps agreeing within about 0.2 eV even for very small structures. A combination of the two methods is found to offer a good trade-off between computational cost and accuracy. Both methods predict nondegenerate midgap states for certain antidot hole symmetries. The inclusion of spin results in a spinsplitting of these states as well as magnetic moments obeying the Lieb theorem. The local-spin texture of both magnetic and nonmagnetic symmetries is addressed.

show abstract

Section: Introductionmentioning

confidence: 99%

Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin

et al. 2009

View full text Add to dashboard Cite

show abstract

“…In the case of graphene, hoppings up to the first or third neighbour on the hexagonal lattice are routinely included, given by either t 1 = −2.7 eV in the case of nearest-neighbour hopping or t 1 = −2.7 eV, t 2 = −0.2 eV and t 3 = −0.18 eV in the case of up to third-nearest neighbour hopping. 4,28 In this work, we choose our unit of energy to be t = −t 1 , scaling the other hopping amplitudes accordingly.…”

Section: Lattice Density-functional Theorymentioning

confidence: 99%

“…For example in transport calculations on graphene, the mean-field approximation has succesfully been applied to allow treatment of systems consisting of few hundreds of atoms. 4 The DFT and the Hubbard model can be combined in several ways. 5 The most obvious choices are either to determine the model parameters based on first principles calculations or to incorporate a Hubbard-type interaction into the DFT exchange-correlation functional, resulting in the so-called DFT+U method.…”

Section: Introductionmentioning

confidence: 99%

Lattice density-functional theory on graphene

Ijäs

Harju

2010

Phys. Rev. B

View full text Add to dashboard Cite

A density-functional approach on the hexagonal graphene lattice is developed using an exact numerical solution to the Hubbard model as the reference system. Both nearest-neighbour and up to third nearest-neighbour hoppings are considered and exchange-correlation potentials within the local density approximation are parameterized for both variants. The method is used to calculate the ground-state energy and density of graphene flakes and infinite graphene sheet. The results are found to agree with exact diagonalization for small systems, also if local impurities are present. In addition, correct ground-state spin is found in the case of large triangular and bowtie flakes out of the scope of exact diagonalization methods.

show abstract

“…However, the atomically precised synthesis of such nanostructures is a key challenge for experimentalists 2,3 and, in this quest, the efforts of several groups [3][4][5][6][7][8][9][10][11][12][13][14][15][16] have provided significant improvement in the controlled synthesis of flat, one-dimensional carbon nanostructures with size and atomic structure gradually closer to "ideal" systems, as studied theoretically [17][18][19][20][21][22][23][24][25] . As graphene and related systems have been extensively studied using a variety of theoretical methods, the problem of experimentally assembling basic small-scale components into hierarchical and useful structures has been addressed by both top-down [3][4][5][6][7][8][9][10][11] and bottom-up [12][13][14][15][16] approaches.…”

mentioning

confidence: 99%

“…This includes electronic structure and thermoelectric transport properties 27,28 and magnetic behaviors 17,19,25,[29][30][31][32] . More importantly, computational modeling has demonstrated that most of the properties of defect free systems can be fine tuned by well-targeted modifications of the atomic structure, either by introducing local lattice reconstructions or by chemical doping [17][18][19]21,22,[33][34][35][36][37][38] . Such modifications are particularly effective when they are operated at the edges of the structure 20,[23][24][25]32,39 , where the atoms have higher energies.…”

mentioning

confidence: 99%

Structural and electronic properties of graphitic nanowiggles

et al. 2012

View full text Add to dashboard Cite

Recent experiments have demonstrated a viable bottom-up strategy to produce narrow and highly ordered nanoribbons, including complex segmented structures called graphitic nanowiggles (GNWs). These defect-free systems are made of successive repetitions of finite-sized graphitic nanoribbons (GNRs) regularly connected at a given angle. Theoretical calculations have shown that these systems exhibit emergent and versatile properties at a level even higher than that found in their basic GNR constituents. Their main structural characteristic is the presence of multiple edge-dependent domains. This atomic structure has a marked influence on their physical properties since GNWs with at least one zigzag sector were shown to accommodate multiple magnetic states. The present detailed study shows how these properties vary with the details of the geometry. We also provide a quantum mechanics based explanation for the origin of GNW's multiple magnetic states. We find that the electronic structure of a GNW is sensitively dependent on the specific way its basic sectors are assembled, as well as on the details of the spin alignment along its edges. As a result, GNWs provide a new means to tune and design systems with desired electronic structure.2

show abstract

Spin-Dependence in Asymmetric, V-Shaped-Notched Graphene Nanoribbons

Cited by 20 publications

References 11 publications

Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin

Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin

Lattice density-functional theory on graphene

Structural and electronic properties of graphitic nanowiggles

Contact Info

Product

Resources

About