Curvature effects on electronic properties of armchair graphene nanoribbons without passivation

et al. 2014

Sci Rep

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Edge-decorated graphene nanoribbons are investigated with the density functional theory; they reveal three stable geometric structures. The first type is a tubular structure formed by the covalent bonds of decorating boron or nitrogen atoms. The second one consists of curved nanoribbons created by the dipole-dipole interactions between two edges when decorated with Be, Mg, or Al atoms. The final structure is a flat nanoribbon produced due to the repulsive force between two edges; most decorated structures belong to this type. Various decorating atoms, different curvature angles, and the zigzag edge structure are reflected in the electronic properties, magnetic properties, and bonding configurations. Most of the resulting structures are conductors with relatively high free carrier densities, whereas a few are semiconductors due to the zigzag-edge-induced anti-ferromagnetism.

“…It shows a θ -square dependence in agreement with the first term of Eq. (1), as seen in carbon nanotubes37. The increase in the total energy is a consequence of the mechanical bending.…”

Section: Resultsmentioning

confidence: 92%

“…2a. This is obtained by fitting the data points from the previous study on curvature effect of nanoribbons37, On the other hand, the second term expresses the electric dipole moments from two ribbon edges based on a classical model of dipole-dipole interaction38. Further discussions will be provided later.…”

Section: Resultsmentioning

confidence: 99%

Geometric and Electronic Properties of Edge-decorated Graphene Nanoribbons

Chang

et al. 2014

Sci Rep

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“…6 For mass production, required in the semiconductor industry, the chemical vapor deposition method for GNRs has been developed. [23][24][25] GNRs are predicted to be more potentially applicable in future nanodevices. [8][9][10] From a geometric point of view, each GNR could be regarded as a finite-width graphene strip or an unzipped CNT.…”

Section: Introductionmentioning

confidence: 99%

Adatom bond-induced geometric and electronic properties of passivated armchair graphene nanoribbons

Phys. Chem. Chem. Phys.

Chung

Yang

et al. 2015

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The geometric and electronic properties of passivated armchair graphene nanoribbons, enriched by strong chemical bonding between edge-carbons and various adatoms, are investigated by first-principle calculations. Adatom arrangements, bond lengths, charge distributions, and energy dispersions are dramatically changed by edge passivation. Elements with an atomic number of less than 20 are classified into three types depending on the optimal geometric structures: planar and non-planar structures, the latter of which are associated with specific arrangements and stacked configurations of adatoms. Especially, the nitrogen passivated nanoribbon is the most stable one with a heptagon-pentagon structure at the edges. The low-lying band structures are drastically varied, exhibiting non-monotonous energy dispersions and adatom-dominated bands. A relationship between energy gaps and ribbon widths no longer exists, and some adatoms further induce a semiconductor-metal transition. All the main characteristics are directly reflected in the density of states, revealing dip structures, plateaus, symmetric peaks, and square-root divergent asymmetric peaks.

“…GNRs exhibit the feature-rich essential properties, such as, electronic structures 5, 32 , magnetic properties 32, 33 , optical spectra 34, 35 , and transport properties 36, 37 . The electronic properties are diversified by changing by the ribbon width (W) 38, 39 , edge structure 38, 40 , edge-passivated dopants 41, 42 , adatom adsorptions 43, 44 , layer numbers 45 , stacking configurations 46 , surface curvatures 47, 48 , mechanical strains 49, 50 , electric fields 51–53 , and magnetic fields 32, 54, 55 . GNRs are expected to be more potentially applicable in future nanodevices 15, 56, 57 .…”

Section: Introductionmentioning

confidence: 99%

Alkali-created rich properties in grapheme nanoribbons: Chemical bondings

Chiu

2017

Sci Rep

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The alkali-adsorbed graphene nanoribbons exhibit the feature-rich electronic and magnetic properties. From the first-principles calculations, there are only few adatom-dominated conduction bands, and the other conduction and valence bands are caused by carbon atoms. A lot of free electrons are revealed in the occupied alkali- and carbon-dependent conduction bands. Energy bands are sensitive to the concentration, distribution and kind of adatom and the edge structure, while the total linear free carrier density only relies on the first one. These mainly arise from a single s − 2p z orbital hybridization in the adatom-carbon bond. Specifically, zigzag systems can present the anti-ferromagnetic ordering across two edges, ferromagnetic ordering along one edge and non-magnetism, being reflected in the edge-localized energy bands with or without spin splitting. The diverse energy dispersions contribute many special peaks in density of states. The critical chemical bonding and the distinct spin configuration could be verified from the experimental measurements.